Thesis document - Jana Milosovicova - Urban Design English

Master’s Thesis in Urban Design:Climate-Sensitive Urban Designin Moderate Climate Zone:Responding to Future Heat WavesCase Study Berlin – Heidestrasse/Europacity-°C-°C-°C+°C+°C-°C-°C-°C-°C-°CPrepared byThesis advisorAssociate advisorJana MilošovičováCSUDDr. Rafael E. PizarroDipl.-Ing. Marco SchmidtDate December 2010

Master’s Thesis in Urban Design:Climate-Sensitive Urban Designin Moderate Climate Zone:Responding to Future Heat WavesCase Study Berlin – Heidestrasse/EuropacityPrepared byJana Milošovičovájana@jm-urbandesign.comThesis advisorDr. Rafael E. PizarroAssociate advisor Dipl.-Ing. Marco SchmidtDate December 2010

ContentsAcknowledgements 5Abstract German 6Abstract 71 Introduction 92 Literature review: The impact of built structures on climate, energy flow and the water cycle 112.1 Urban heat island (UHI) 132.2 Basic energy, heat and water cycle characteristics 15Solar radiation and its impact on Earth 15Water cycle 192.3 The impact of urban form and geometry on urban climate 21Size of the city 21Density and compactness 22Urban geometry 23Impact of the street orientation on insolation 26Ventilation 262.4 The effects of land use on urban climate 31Water in urban design – Water bodies 31Vegetation in urban design – Parks and green areas 322.5 Literature review: Lessons learned 343 Climate-Sensitive Urban Design (CSUD) in moderate climate zone 363.1 Review of existing CSUD guidelines 37Berlin’s documents addressing CSUD 383.2 Proposed CSUD Guidelines 40Urban form – density/compactness and geometry 40Ventilation 41Solar radiation 42Water cycle and Vegetation 44Special design details of buildings affecting outdoor conditions 46General recommendations 473.3 Examples of CSUD in built urban design projects 48Institute of Physics Berlin-Adlershof 48Castello mixed-use development, Berlin, Germany 482Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Bo01, Western Harbour Malmö, Sweden 49Heinrich-Böll Settlement, Berlin 49Kirchsteigfeld, Potsdam 493.4 Climate-Sensitive Urban Design (CSUD) – Case Study Heidestrasse/Europacity 50Action category ‘Urban form – density/compactness and geometry’ 53Action category ‘Ventilation’ 54Action category ‘Solar radiation’ 54Action category ‘Water and Vegetation’ 55Action category ‘Other design- and/or general recommendations’ 564 Conclusions 58Glossary 62Sources 66List of figures 71List of tables 75Appendices 76Appendix 1 Climatic effects of various urban land use categories 77Appendix 2 City of Toronto’s Study on Green Roof Benefits 80Appendix 3 BAF - Biotope Area Factor 81Appendix 4 Tempelhof Study 83Appendix 5 Institute of Physics Berlin-Adlershof 84Appendix 6 Castello mixed-use development, Berlin-Lichtenberg 86Appendix 7 Bo01, Malmö, Sweden 88Appendix 8 The LEED-ND provision for UHI effect mitigation 91Appendix 9 Posters Climate-Sensitive Urban Design – Case Study Heidestrasse/Europacity 92Contents3

4Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

AcknowledgementsI would like to thank Prof. Gerhard Hahn-Herse, who was the first toteach me the importance of climate in urban planning and design considerationsand who awoke my interest in this topic. I would also liketo thank Heinz Brandl, Andre Heinzel, and Werner Schlömer from Sen-Stadt Berlin, who offered their insights into Berlin’s Climate-SensitiveUrban Design and Planning approaches.My particular thanks go to my Thesis advisors: Marco Schmidt, for hisscientific knowledge and practical experience, without which the basisfor this work would not have been as solid, and for calling things bytheir right names and putting them into the proper context, somethingthat I myself had been trying to do for years; and last, but far fromleast, Rafael Pizarro, my main advisor, for his constructive criticism anddemanding but patient and, most of all, supportive guidance.5

Abstract Deutsch/GermanAusgehend von den klimabezogenen Problemen in Städten, liegt derFokus dieser Arbeit auf den Auswirkungen der physischen Struktur dergebauten Umwelt auf das Mikro- bis Makroklima. Die Forschungsfragelautet: “Wie sollen sich die Stadtform und Stadtgestalt den wachsendenAnsprüchen an Klimagerechtigkeit anpassen?”.In der Arbeit wird zuerst über die klimatischen Aspekte der Städteim kühlen gemäßigten Klima recherchiert. Dabei stellt sich heraus,dass das Phänomen der städtischen Wärmeinsel erheblich zu denAuswirkungen der - in der Zukunft immer häufiger zu erwartenden -Hitzewellen beiträgt. Die Rechercheergebnisse zeigen, dass die Art undWeise, wie die städtischen bebauten Flächen und die urbane Geometriegestaltet werden, einen maßgebenden Einfluss auf die Ausprägung vonstädtischen Wärmeinseln hat, und diese aber wiederum durch eineSteuerung der natürlichen Energieflüsse lindern kann. Dies geschiehtmit der gezielten Umwandlung der Sonnenstrahlung, insbesondere mitder Verbesserung des Verhältnisses von verdunstenden Oberflächenund von bewachsenen Flächen in den Städten, und mit einer bewusstenAnpassung städtischer Proportionen, die mit Hilfe von Beschattung undBelüftung für einen optimalen Kühleffekt in heißen Sommern sorgen.Um sich mit dem Problem der städtischen Wärmeinseln umfassendaus einanderzusetzen, wird der Literaturrecherche zufolge ein komplexesBündel von städtebaulichen Maßnahmen benötigt. Dazu müssenviele Strategien einbezogen werden: eine effektive Kombination vonStadtform (geeignete städtebauliche Dichte, Orientierung von Straßenund Gebäuden, Höhen, etc. für ein gewünschtes Verhältnis von Einstrahlungund Belüftung) mit Landschaftsgestaltung (dezentrale Regenwasserbewirtschaftung,Dachgärten und begrünte Fassaden, begrünteFreiraumflächen für eine effiziente Luftkühlung) und Gebäudedesign.Um das Vorhandensein solch städtebaulicher Leitlinien zu prüfen, werdenin der Arbeit klimarelevante städtebaulichen Leitlinien und Vorgabenfür die Stadt Berlin und für andere Städte in der kühlen gemäßigtenKlimazone untersucht, um ihre Schwächen und Stärken im Bezug aufdie Empfehlungen der Klimatologen und Klima-spezialisierten Stadtplaner/UrbanDesigner zu identifizieren. Eine der Feststellungen ist,dass solch komplexe Leitlinien, die die Befunde der Literaturrecherchereflektieren würden, nicht existieren. Diese Lücke feststellend, wird inder Arbeit anschließend ein Bündel von klimasensiblen städtebaulichenLeitlinien zusammengestellt, dass auf die Linderung der städtischenWärmeinsel und auf die Herabsetzung der Auswirkungen der zu erwartendenHitzewellen zielt.Um zu veranschaulichen, wie diese in Text und Grafiken dargestelltenLeitlinien angewendet werden können, wurde als Fallstudie das städtebaulicheKonzept für das zukünftige Berliner Stadtquartier Heidestraße/Europacity ausgewählt, um seine klimasensible Strategien gegen dieFeststellungen in dieser Arbeit kritisch zu überprüfen. Als der letzteSchritt werden Anpassungen gegenüber dem ursprünglichen Plan sowiedas Konzept vertiefende und ergänzende Empfehlungen vorgeschlagen.6Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

AbstractBased on the climate-related problems in – and caused by – cities, theThesis’ focus is on the physical structure of the built environment andon how this affects the micro- to macroclimate. First, the literatureon climatic aspects of cities in cool moderate climate is reviewed andthese characteristics are described. The typical features are in particular:a) the energy flow and water cycle changes resulting from sealingthe surfaces, creating high concentrations of man-made built objectsand withdrawing vegetation from urban areas; b) the urban form andgeometry affecting the insolation and ventilation conditions in cities;both a) and b) resulting in the Urban Heat Island (UHI).The findings conclude that it is the way the urban built surfaces andthe urban geometry are designed that may alleviate the UHI effectthrough affecting the natural energy flow. This happens through thetransformation of solar radiation, via enhancing the ratio of evaporativesurfaces and vegetated areas in cities; and via street orientation andbuilt masses’ proportions that with the help of shading and ventilationprovide maximal cooling effects during hot summers.It is thus stated that to address the problem of the UHI comprehensively,a set of urban design guidelines should be a connection betweenthe building design, landscape design and urban form. All strategiesmust be included, and a combination of urban form (considering appropriateurban density, orientation of streets and buildings, buildingheights, etc. for a desired ratio of incoming radiation and ventilation)with landscape design (means, decentralized rainwater management,rooftop gardens, vegetated ground areas, etc.) is the best to be trulyeffective. The thermal comfort in buildings however is not the objectof this Thesis.The Thesis then revises climate-related urban design guidelines andpolicies for the City of Berlin and for other cities in the cool moderateclimate zone; to identify the weakness and strengths related to therecommendations by climatologists and climate-specialized urban designers/planners.Reflecting the findings in the literature review, a setof “Climate-Sensitive Urban Design (CSUD) Guidelines” that addressesthe UHI mitigation and helps alleviate the effects of the anticipatedheat waves in cool moderate climate cities, is recommended and presentedin text and graphics. To illustrate how such guidelines can beapplied, the urban design proposal for Berlin’s Heidestrasse/Europacityhas been chosen as a case study to critically examine its alleged CSUDstrategies against the findings in this Thesis. As a final step, amendmentsto the original plan as well as complementing recommendationsare suggested.7

8Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

1 IntroductionResearch QuestionsThe research questions guiding this Thesis are:1. How should urban design guidelines change in cool moderate climate1 cities to respond more effectively to extreme heat waves as aresult of climate change?2. How does the application of these guidelines affect urban designprojects?Thesis justificationWith the anticipated climate change, the temperature in many citieswill rise dramatically during the summer months. Although it is thoughtthat the heat waves will be a problem particularly grave in subtropicalcountries (Kay 2007), and especially in desert areas, the effects onsome higher latitude countries can be equally devastating. The 2003heat wave in Europe with the death toll of over 50,000 people 2 is anexample of the potential catastrophic consequences. This Thesis questionswhy European cities were not prepared for the heat wave of the2003 and it anticipates that such extreme summer events will likelyoccur again in the not so distant future. 3 Given this problematic, thisthesis sets out to revise existing climate related design guidelines inBerlin and other cool moderate climate cities, and propose changes oradjustments to such guidelines.Fig. 1 The cool moderate (temperate) climatezone takes over large parts of Western, Centraland Eastern Europe, the North-East of USAwith the adjacent part of Canada, parts of Japanand China and some areas of Australia andNew Zealand (Climate classification accordingto Paffen and Troll). (© Bildungshaus SchulbuchverlageWestermann)The Thesis’ presumption for the lacking guidelines is that in the pastyears, the common focus of local and global strategies to mitigate climatechange has been on the reduction of greenhouse gases (IPCC2007). The increasing urban temperatures due to the Urban Heat Island(UHI) effect however is one climate-related problem that has notbeen lent enough attention in the urbanization process nor has beenconsidered a problem in global warming. This Thesis focuses on designguidelines and strategies to address the UHI as another importantstrategy to tackle global climate change.The Thesis is based on the premise that land use changes – in particulardeforestation (fig. 2), and urbanization (fig. 3), are significantlyinfluencing the climate at both macro- and micro-scale level. In Germany,the urbanization is 104 ha/day 4 (despite the since 2001 shrink-1 Although the built form in the moderate climate zone is being required to respondto the seasonal conditions, the design focus of this Thesis will be on theextreme heat events occurring during the summers – their intensity anticipatedto increase in the next decades.2 The data about the total number of deaths related to the 2003 Heatwave varysignificantly: The Earth Policy Institute, 2006, states a number of more than52,000 people; J.-M. Robine et al., 2008, state more than 70,000 deaths thatoccurred in the summer 20033 See, for example, the WWF study on the anticipated effects of climate change:“Kosten des Klimawandels. Die Wirkung steigender Temperaturen auf Gesundheitund Leistungsfähigkeit.” WWF Germany, Frankfurt am Main, 2007.4 Statistisches Bundesamt Deutschland, 2010Fig. 2, 3 Deforestation (above, © GIZ / LisaFeldmann) and urbanization (below) are amongthe main factors that significantly affect the climate.9

ing population 5 ) – more than a half of it being sealed surface 6 , whichinevitably and directly affects the climate.Fig. 4 “Natural” landscape: 75% evapotranspiration,25% groundwater rechargeand runoff,86% of “consumed” net radiation (Schmidt2008)Fig. 5 Urban “landscape”: reduced evapotranspiration,increased thermal radiation, increasedheat, “urban heat island”The Thesis claims that the physical character of built structures – whichaffects the climate by causing the UHI effect – has not been properlyreflected in the way in which we have been building cities and howwe have been reflecting on, and involving, natural processes (energyflows and water cycle) in urban design and planning. Therefore, thenatural parameters will be examined, and the necessity for their betterunderstanding in the professional guidance of the urbanization processwill be stressed.MethodThe Thesis focuses on the physical structure of the built environmentand on how this affects the climate. First, the literature on climaticaspects of cities in cool moderate climate is reviewed and these characteristicsdescribed. The typical features are in particular: a) the energyflow and water cycle changes resulting from sealing the surfaces, creatinghigh concentrations of man-made built objects and withdrawingvegetation from urban areas (fig. 4 and 5); as well as b) the urbanform and geometry affecting the insolation and ventilation conditions incities; both a) and b) resulting in the Urban Heat Island (UHI).Second, the Thesis revises climate related urban design guidelines andpolicies for the City of Berlin, as an exemplary city in the cool moderateclimate zone, and for other cities in the same climate zone, to identifythe weakness and strengths related to the recommendations by climatologistsand climate-specialized urban designers/planners.Third, reflecting the findings in the literature review, a set of “Climate-Sensitive Urban Design Guidelines” (CSUD) addressing the UHI mitigationand helping alleviate the anticipated heat waves in the coolmoderate climate cities, is recommended and presented in text andgraphics.And fourth, to illustrate how such guidelines can be applied, the urbandesign proposal for Berlin’s Heidestrasse/Europacity has been chosen asa case study to critically examine its alledged CSUD strategies againstthe findings in this Thesis. As a final step, amendments to the originalplan as well as complementing recommendations are suggested.5 Statistisches Bundesamt Deutschland, online6 Bundesinstitut für Bau-, Stadt- und Raumforschung, online10Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

2 Literature review: The impactof built structures on climate,energy flow and the water cycleThis section explains the impacts of the built environment on climate.It provides urban designers with an understanding for how the physicalcharacter of the built environment affects climatic conditions locally, onthe cities’ and regional levels. The chapter introduces phenomena thatdistinguish urban climate from rural, and that influence the characterof the urban atmosphere, namely, the radiation and energy flows andthe near-ground air circulation.Recent findings in planetary climate research (Kravčík et al. 2007,Schmidt 2009) suggest that the climate change and the changes in thespatial distribution of weather occurrences are to a significant extentrelated to a decrease of evapotranspiration, caused by the change inland use. In urban areas, the lack of evapotranspiration results in theproblem of temperature extremes caused by the lack of vegetativecover which results from the sealing of surfaces during the urbanizationprocess. This affects the energy flows and temperatures in cities aswell as beyond their boundaries. Kravčík et al. focus on the “(…) alleviatingthe effect of climate change by improving management of waterand vegetation” (Kravčík et al. 2007, p. 23). As a result, the authorsrecommend increasing the presence of vegetated surfaces in cities inorder to retain rainwater on-site to increase water vapour in the air,which in turn lowers surface temperatures (Schmidt 2009).Another measure to lower urban temperatures pursued by most authors(Sass, online; Givoni 1998, p. 284; Emmanuel 2005; Gartland2008) is changing the albedo, the surface reflectance of the system.This implies that dark (low albedo) surfaces should be replaced by light(high albedo) surfaces whenever possible, so that less solar radiation isabsorbed and thus the surface temperatures kept at the minimum.In general, the commonly acknowledged sources seem to concludethat it is particularly rising the surface reflectance (e.g. Gartland 2008;Sass, online) and reducing CO 2(e.g. IPCC Report 2007; Roaf 2009)what can effectively mitigate the extreme temperatures in cities. Thesesources however fail to understand the complexity of the natural parametersand the need to involve these in the urban design process.Other authors consider the orientation of streets and the urban form(Givoni 1998, Emmanuel 2005, Herrmann and Matzarakis 2010) to bethe decisive factors in affecting temperatures in cities. The most comprehensivesources covering topics on climate considerations in urbandesign, with a strong focus on urban form and geometry, appear to bethe books by Baruch Givoni, “Climate Considerations in Building and UrbanDesign” (1998) and by Rohinton Emmanuel, “An Urban Approach toClimate-Sensitive Design – Strategies for the Tropics” (2005). Unfortunately,these sources omit the issue of designing in moderate climates.Additionally, Givoni (1998) and Emmanuel (2005) incline to underestimatethe importance of natural energy flows and water cycle as well11

as the immense climatic effects of vegetation in built-up areas. Theseauthors acknowledge the problem of evapotranspiration loss; howeveravoid suggesting consequent design solutions. Givoni, for instance, explicitlydenies the possibility of planting on buildings and in areas oncetaken by buildings (Givoni 1998, p. 282), undervaluing the notion thatthe high temperatures can be mitigated with the help of vegetated builtsurfaces.While the environmental aspects of urban climate are being avoidedin most of the urban design-related sources, there is a comprehensiveliterature on these issues, such as “Stadtökologie” (Urban Ecology) bySukopp and Wittig (1998) or “Urban Ecology” by Marzluff et al. (2008).These sources however give only general text recommendations forclimate-related urban planning and omit particular urban design recommendations.Not surprisingly, some of the authors disagree on what measures areuseful to tackle the global warming effects on cities, for example thosebased on management of water cycles. Givoni, for example, states that“some of the factors which affect the urban heat island are meteorogicaland not subject to human intervention, such as cloudiness and theregional wind speed” (Givoni 1998, p. 245); while, in turn, other authorsclaim that it is human intervention reflected in the design of citiesthat restrains the evapotranspiration from formerly vegetated areas(Kravčík et al. 2007, p. 14-15). This has an effect on the cloudiness andthe amount of solar radiation that reaches the city, increasing the temperatures.Urban design also plays an important role in enabling naturalventilation conditions by steering regional winds into cities (e.g. Kuttlerin Marzluff 2008).Another finding is that the notion of albedo seems to be overemphasized.It is commonly believed that a higher surface reflectance affectsthe total energy balance, thus lowering the urban heat island effect(Sass, online; Emmanuel 2005; Gartland 2008; Givoni 1998, p. 308).However, it seems that although the microclimate temperatures areaffected, the effect of solar reflection on the total radiation balance ofthe city (and on the urban heat island) is in fact minimal. See more onp. 17-18.As briefly introduced above, the thorough literature review on the effectsof the built form on climate indicates that there are many factorsin the physical structure of the city that influence urban climaticconditions. This implies that there is not only one single measure to beapplied in order to achieve a well-balanced and physically acceptableurban climate. Much more than that, a well-thought-out set of measuresmust be implemented. According to the given local conditions, onemeasure might be of higher priority and weighting than another.In the sections 2.1 – 2.3, a detailed description of the findings, basedon the reviewed literature, will be presented. The aim is to managea thorough knowledge base for the main subject of this Thesis, the“Climate-Sensitive Urban Design”.12Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

2.1 Urban heat island (UHI)Only since the 1995 severe heat wave in Chicago, which contributedto a significant number of deaths, particularly among senior citizens,or the 2003 heatwave in central Europe, which had a death toll of tensof thousands of people, has it become clear that the temperature extremesare tightly connected to the urban climatic conditions, and tothe phenomenon of the Urban Heat Island (UHI) (Kropp and Reckien2009, p. 4). The UHI, besides increasing the daily urban temperaturesto the non-conforming extent (and thus causing higher mortality ratesdue to blood circulation collapse), has a severe effect on the abilityof people to rest and to recuperate from heat stress during the nighthours. If the temperature at night is not cooled down to below 25°C,the sleep depth is lowered and the regeneration function of sleep lost(Hahn-Herse 1997, Section ‘Climate’, p. 20). This may cause severehealth problems, and was the main reason for death of thousands,prevailingly elderly, people and people with cardiovascular problemsduring the 2003 European heat wave.The UHI means the difference in the air temperature betweenan urban area and its surrounding natural environment(fig. 6). The main occurrence of this effect is at night,when the surrounding rural environment cools down muchfaster than the city, where the heat stored in the buildingmass and roads is released only slowly into the atmosphere.For example, the temperatures in the centre of Berlinon a clear windless night can reach 9°C higher than itsoutskirts (Urbis Limited 2007, p. 15).As various authors/sources 7 explain, in urban areas, buildingsand paved surfaces have replaced natural landscapes,significantly increasing the rainwater runoff and reducingthe natural cooling effects that shading and water evaporationfrom soil and leaves ordinarily provide. Instead, solarenergy is absorbed into roads, buildings’ walls and rooftops, causingthe surface temperature to become higher than the ambient air temperatures.Meanwhile, tall buildings, closed building blocks and narrowstreets reduce airflow and heat the air trapped between them. Wasteheat from vehicles, industrial plants, buildings (especially from heatingand air conditioners) adds warmth to the surroundings, further exacerbatingthe heating effect. In addition, the urban “greenhouse” effectcontributes with long-wave radiation reflected from polluted urbanatmosphere. These phenomenons, known as “urban heat island”, canraise air temperature in a city by 10°C and even more.Fig. 6 Urban heat island profile (Kravčík et al.2007, p. 28)The UHI augmenting factors are (fig. 7):• Evapotranspiration loss: Reduced green spaces in cities,replaced by sealed materials 8 , lead to more sensible (thermal) heattransfer;7 The Physical Environment; EnvironmentAbout; Kravčík et al. 2007, p. 14-15;Schmidt 2009; Emmanuel 2005, p. 24-25; Sass, online8 Which have a strong three-dimensional structure, and thus have a higher surfaceproportion of man-made materials than the original environment.2 Literature review: The impact of built structures on climate, energy flow and the water cycle13

• Urban geometry: Tall buildings within urban areas provide multiplesurfaces for the reflection and absorption of sunlight, increasing theefficiency with which urban areas are heated – called the urbancanyon effect. Another effect of buildings is the blocking of wind,which also inhibits cooling by heat transport (Wiki UHI, online);• Anthropogenic heat waste coming from vehicular traffic, air-conditioning,electric devices such as computers, refrigerators etc.;• Urban “greenhouse” effect: Long-wave radiation emitted frompolluted urban atmosphere.Matzarakis (2001) stated that it is the thermal characteristics of constructionmaterials (particularly the level of surface sealing) and theeffects of urban geometry that influence the UHI extent in the mostsignificant way (Matzarakis 2001, p. 50-51). Interestingly, the immissions-relatedgreenhouse effect is “relatively unconsiderable” (Matzarakis2001, p. 51), compared to the two above mentioned factors. 9Fig. 7 Causes for UHI (Emmanuel 2005, p.25)Emmanuel (2005) summarized approaches explaining the nature of urbanheat islands, and stated that it is the energy-based approach thatnot only explains the causes, but also points to urban design solutions.According to this summary, the primary energetic effect of urbanization,causing the UHI is “(…) partitioning of more heat into sensible (=thermal heat) rather that latent form (= thermal energy withdrawn inthe process of vaporization of water, not connected with increasing oftemperatures)” (Emmanuel 2005, p. 25). The imperative message thusis to bring more evapotranspirative surfaces back into cities. 10The evapotranspiration of water affects the air humidity, which influencesthe intensity of the UHI. The higher the air humidity, the lowerthe temperature differences between the city and its surrounding naturalenvironment. In the cities with higher air humidity in coastal regionsof mid-latitudes (Park 1987 in Marzluff 2008, p. 241) and in tropicalhumid climates, the intensity of the UHI is much lower (Matzarakis2001, p. 111). The increase in air humidity to tackle high urbantemperatures with the help of evapotranspiration is thereforeessential.A fundamental argument of this Thesis however is that it is both surface/landscapedesign and urban form that have a significant effect oneither increasing the UHI or in reducing it. The way in which we designcities might thus contribute to the alleviation of UHI, maybe even withpositive effects on regional and global climate. Interestingly, even theIPCC Report 2007 only mentions the relevance of the reduction of GHGemissions to mitigate the climate change, but not the direct effect ofland use modification – and thus the changed surface characteristicsand temperatures and options for their mitigation.Fig. 8 Values of solar radiation on a clear day(above) and on a cloudy day (below). Recordedon 18 July 2006 and 3 August 2006, in Třeboň,Czech Republic (Kravčík et al. 2007, p. 24).9 And, since urban design does not offer ways to deal with the emission of pollutantsitself, only on their trapping (with providing ventilation exchange betweenthe pollution sources, such as highways, and compensation areas, such as urbanparks; and with enhancing greenery – all discussed in the next chapters), nodetailed attention will be given to the pollution issue in this Thesis.10 Key terms are highlighted in bold typeface as takeaway for the reader who isinterested in applying the CSUD guidelines to his/her projects.14Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

On the premise of appointed alleviation of the extreme summertemperature events in the cities in cool moderate climate zone,the aim is to eliminate the temperature differences betweenthe urban area and its surrounding environment by loweringthe urban temperatures. The subject of this Thesis is to composea set of measures that would help achieve this goal.2.2 Basic energy, heat and water cyclecharacteristicsTo understand better how the energy processes and the water cycleare influenced by cities (both affecting the temperatures and climate),a few factors related to the energy flux and water cycle in rural andurban areas in moderate climate are explained in this section. Thesefactors are the incoming solar radiation (and its interaction with waterand vegetation), storage heat, surface reflectance (albedo), and thewater cycle.Solar radiation and its impact onEarthIn the moderate zone, the annual input of solar radiationimpinging the surface of the Earth reaches avalue of about 1,100 kWh/m 2 per year. The amountof solar energy falling on the Earth’s surface ondays of clear skies differ from that on days of overcastskies – as solar radiation is being partially absorbedby gases and water vapour in the atmosphere(Kravčík et al. 2007, p. 24) (fig. 8). Of the amount ofenergy that reaches the Earth’s surface, about 7.3%is reflected back into space in the form of shortwaveradiation, 12.7% radiates as long-wave (thermal)radiation and 41.8% is consumed in the circulationof water for evaporation (Schmidt 2010). The latter,also called ‘latent heat’, is the only form of theEarth’s surface reaching transformed solar radiationthat is not connected with increasing the temperatures(Kravčík et al. 2007, p. 25). Especially in ruralareas, if solar radiation falls on a surface well stockedwith water, a significant part of the incident solar radiationis transformed into latent heat by plants inthe process of evapotranspiration. Only the remainingpart is converted into sensible heat and resultsin temperature differences, another small part beingreflected, or used for photosynthesis (Givoni 1998,p. 270), see also fig. 9.In sealed and drained urban areas, as in the figure10, most of the incident solar radiation is convertedultimately into sensible (thermal) heat, which raisesthe air temperature and contributes to the heat islandeffect (Givoni 1998, p. 270-271).Fig. 9 Global radiation balance as annual mean of one m 2 on earth(Schmidt 2010)Fig. 10 Global radiation balance of a black bitumen roof as indicatorfor urban radiation changes (Schmidt 2010)2 Literature review: The impact of built structures on climate, energy flow and the water cycle15

-°CFig. 11 Photographs of thin vegetation inthe visible spectrum (above) and in the infraredspectrum (below). The bare surface ofthe ground is visibly warmer than the surfaceof the leaves cooled by transpiration. Třeboň,Czech Republic, 12 July 2002, 10:00 (Kravčíket al. 2007, p. 27)-°C+°C+kWhAs the water evaporates from a surface, latent heat is removed withthe water vapour effectively cooling it. 11 This process happens throughboth evaporation of water from a surface and transpiration throughplants. As a result of the evapotranspiration process, the air in greenareas is cooler than the air in built-up areas covered by asphalt orconcrete (Givoni 1998, p. 307). The cooling effect of plants caused byevapotranspiration is apparent in the figure 11. The pictures show thatthe leaves of the plants are, thanks to transpiration, visibly cooler thanthe surrounding soil (Kravčík et al. 2007, p. 27).Therefore, water surfaces, soil saturated with water and vegetation allhave a significant cooling effect and air-conditioning capability (Kravčíket al. 2007, p. 15). The imperative message thus is that the design ofsurfaces in the urban environment needs to support evapotranspirationas main priority in urban design.Translated into designer’s language, trees, vines and high dense shrubsnext to walls, pergolas and roof vegetation have impacts on the climateon and around buildings – they protect by their shading and cooling effectfrom overradiation, while certain ventilation is still provided. 12 (Ifdeciduous, the vegetation will not have negative impacts such as reducingof the desired solar gain in winter or increase in walls’ wetness.)Transpiring plants, especially trees, are the perfect natural airconditioningsystem. On the crown of a large tree of about 10 m in diameter,with a surface area of 80 m 2 , there falls each day about 450 kWh ofsolar energy (4-6 kWh/m 2 ). Part of the solar energy is reflected, partis absorbed by the soil and part is converted into heat. If such a treeis well stocked with water, particularly when planted over vegetatedand non-sealed surfaces (Meier et al. 2010), it evapotranspires some400 litres of water each day, consumig about 280 kWh. This amountof energy represents the difference between the shadow of a tree (absorbedand reflected energy is 170 kWh) and the shadow of a parasolwith the same diameter (absorbed and reflected energy is 450 kWh)(fig. 12). In the course of a sunny day, then, such a tree cools with apower equal to 20-30 kW, power comparable to that of more than 10air-conditioning units (Kravčík et al. 2007, p. 27).Additionally, ground cover by plants around a building reduces the reflectedsolar radiation emitted toward the walls, thus lowering the heatgain in the summer.However, unlike in case of vegetated surfaces, where the energy isFig. 12 A tree with 10 m diameter “consumes”solar energy and transforms it intolatent heat in the process of evapotranspiration(left) / Shading devices have the sameshading effect as trees, however emit additional280 kwh of absorbed and reflected solarradiation, which heat up the atmosphere(right)11 Evaporation of a liquid takes place at every temperature. The specific latent heatof water under normal pressure and at a temperature of 25 °C is 2243.7 kJ/kg- which is the amount of solar energy consumed to evaporate each liter of waterwithout increasing the temperature (This same amount of heat is released laterduring condensation of the water vapor in a colder place). If the water howeveris not present on land, a great part of the solar energy is changed into sensibleheat and the temperature of the environment sharply increases (Kravčík et al.2007, p. 25). It is important to add, that with every 10 g of by the plant createdorganic material, not only about 2.1 kWh of thermal energy will be “consumed”,but also about 14g of the commonly discussed CO 2(Kravčík et al. 2007, p. 32)!12 The results of various experimental studies on the positive climatic impacts ofvegetation in urban areas and in close proximity of, or on buildings, conductedby various authors, were summarized by Givoni (1998, p. 309-318).16Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

transformed into latent heat and thus contributes to evaporative cooling,the non-respirative built surfaces in urban environments absorbheat, store it and then slowly release the trapped energy in form ofheat. This energy absorbed by various materials (construction materials,pavement, soil, etc.), known as ‘storage heat’, is expressed bythe specific heat capacity 13 (Sass, online). The values for commonlyused materials are shown in Table 1.“(…) water and vegetation play a decisiverole in the transformation of solarenergy falling on the earth’s surface(…)” (Kravčík et al. 2007, p. 8)Table 1. Specific heat capacity of various materials (Source: EngineerToolBox, online)MaterialSpecific Heat Capacity- cp - kcal/kg o C(4186.8 J/kg K = 1 kcal/kg o C)MaterialSpecific Heat Capacity- cp - kcal/kg o C(4186.8 J/kg K = 1 kcal/kg o C)Asphalt 0.22 Sand 0.19Brick, common 0.22 Sandstone 0.22Clay 0.22 Soil, dry 0.19Concrete, stone 0.18 Soil, wet 0.35Concrete, light 0.23 Stone 0.2Glass 0.2 Water 4.19Granite 0.19 Wood, balsa 0.7Limestone 0.2 Wood, oak 0.48Plaster, light 0.24 Wood, white pine 0.6Some authors suggest not to attribute much weighting to the storageheat parameter. Oke, for example, “found no significant correlation betweentypes of man-made surfaces and heat island intensity. The onlysignificant difference observed was between man-made and naturalsurfaces. Thus, concrete surfaces and asphalt paving, brick walls andcinder blocks, all contribute more or less equally to the problem ofurban heat build-up, while tree-covered areas show remarkable reductionin heat build-up” (Oke 1981 in Emmanuel 2005, p. 24).This implies that in the city – where most of surfaces are impermeableto water and the precipitation runs off rapidly into the sewer system(or is collected into rainwater tanks) rather than being availablefor evapotranspiration and its cooling effect on-site (Sass, online), thelarge-scale removal of vegetation and draining is connected with theabsorption of solar radiation, formation of “hot plates” on land and withthe release of a colossal amount of the stored heat. “Sensible heat releasedfrom just 10 km 2 of drained land (a small town) for a sunny dayis comparable with the installation power of all the power plants in theSlovak Republic (6,000 MW)” (Kravčík et al. 2007, p. 28).The distribution of solar energy on Earth is also determined by the amountof reflected solar radiation. Albedo, or surface reflectance, expressesthe ratio of reflected radiation out of total radiation. For example, vegetationreflects about 5-30% of shortwave solar radiation and hence hasan albedo of 0.05-0.3; a colour-painted wall reflects up to 35% (albedo0.35), while a white-painted wall reflects up to 90% of solar radiationand has an albedo of 0.9 (fig. 13) (Kravčík et al. 2007, p. 25).13 Energy needed to raise the temperature of 1 kg of a substance by 1 degreeFig. 13 Albedo of various materials in urbanenvironment2 Literature review: The impact of built structures on climate, energy flow and the water cycle17

Fig. 14 Photograph of the square and adjacentpark in Třeboň, Czech Republic, takenwith a thermal camera. The differences in temperaturesbetween the vegetation, façades androofs of the houses is visible. (Kravčík et al.2007, p. 33)Fig. 15 Aerial view of an industrial site in Berlin(Google)Fig. 16 Bioclimatic categorization of the samearea as a “burden” area (Environmental AtlasBerlin)As such, low albedo implies higher surface temperatures since largeramounts of energy are not reflected, but absorbed. This applies in caseof dark non-vegetated surfaces, in case of vegetated areas however,the cooling process of evapotranspiration takes place (Sass, online;Kravčík et al. 2007, p. 25). Vegetation has a darker colour and thus alower albedo than many other surfaces, e.g. white painted walls. Plantshowever, independently of reflectance, cool through evapotranspiration(fig. 14). This cooling effect of vegetation, evident from the infraredphotographs of the square and park in Třeboň (CZ), is much higher incomparison with the effect of reflectance. The temperature of the roofsand façades exceeds 30°C, whereas the temperature of the trees in thepark is around 17°C (Kravčík et al. 2007, p. 27-28). We can thus concludethat evapotranspiration is more effective than albedo.A hypothesis resulting from previous findings is, that even if albedoraising helps lower the air temperatures and the PET 14 by reflectingsolar radiation back into the atmosphere, this happens solely on local,microclimate level in the proximate distance to the particular surface;and it has no influence on the extent of the UHI and on the total heatamount in the atmosphere. This is because by reflecting, no transformationof incident solar radiation into the latent heat (the form of heatwith evaporative cooling effects) takes place. This can be confirmed inthe graphics, figure 15 showing a high-reflective surface of an industrialarea in Berlin; figure 16 showing the temperature “burden” impact ofthe same site. Thus, raising the surface reflectance should not be seenas “the only really effective way (…) to affect the radiation energy balance”as pointed out in Sass (online) and suggested by other authors(Gartland 2008). To truly affect the temperatures, building greeningmeasures should be preferred.The effectivity of the albedo parameter in densely built-up urban areasis arguable also due to another aspect: In an urban area, a great partof the reflected rays hits walls of adjacent buildings, and thus only asmall part of the solar radiation impinging on walls and streets is reflectedupward to the sky; most of the radiation being absorbed in thewalls of the buildings, regardless of the colour, to be stored as heat andreleased back into the atmosphere later (Givoni 1998, p. 269).For the above reasons, greening should have a higher priority indesigning of surfaces rather than creating light and reflectivesurfaces. Raising albedo values of non-vegetated surfaces should beseen as a surface adjustment measure of secondary importance, andshould be applied where no greening measures are possible (as e.g. incase of road infrastructure). Nonetheless, surface albedo is one offactors influencing local surface temperatures and should notbe omitted when deciding about the character of constructionmaterials, even when these are to be covered with vegetation. Dark,non-vegetated (low albedo) surfaces should be replaced bylight and reflective (high albedo) surfaces so that less sunlightis absorbed. For the purpose of glare avoidance, other light coloursmay be used instead of white.14 Physiological Equivalent Temperature, see glossary18Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

However, greening of surfaces and albedo rising are not the only aspectsthat significantly influence the energy balance of cities. The naturalwater cycle and (rain)water management are another issues to beconsidered when pursuing climate-sensitive urban design.“Water and water vapor influence inthe most significant way the climate onEarth” (Kravčík et al. 2007, p. 14).Water cycleIn the natural environment, about 75% of rainwater evaporates fromthe land and thus stabilizes the climate and the temperatures. In urbanareas however, as pointed out before, the lack of evapotranspiration isa major cause of the urban heat island – and thus the evaporation ofrainfall should have the highest priority (SenStadt Berlin and TU Berlin,p. 11). The consideration of water – in fluid form or as water vapourincreasing the air humidity – has however been widely underestimatedand overlooked in urban design considerations. In this section, it willbe reported on the importance of water and possibilities of restorationof the small water cycle through urban design.The small water cycle (fig. 17) is characteristic for a hydrologicallyhealthy country, where solar radiation evaporates water from waterbodies, soil and plants into the atmosphere. There, water representsthe largest energy conversion of incoming shortwave solar radiation,playing an important role: “the less water in the atmosphere, theweaker its moderating effect on temperatures” (Kravčík et al. 2007, p.14). The majority of evaporated water in the atmosphere condensesand falls down again at night in the given region or its surroundings –alleviating the UHI effect, whose intensity is most significant at night.In urbanized, built-up areas, there is an extensive disruption of evaporativevegetation cover and of permeable surfaces (fig. 18) and thus,a high proportion of the rainwater is led into the sewerage, instead ofbeing evaporated. “Nearly all rainwater from the cities of Europe is carriedto rivers and eventually to the seas from paved and roofed areasby rainwater sewers” (Kravčík et al. 2007, p. 43-44). To illustrate thesituation in one particular city, only in Berlin it is annually 35 millionm 3 (SenStadt – Rainwater I, online). The effects are a longterm drop ingroundwater supplies beneath the paved and roofed surfaces, a fall inatmospheric humidity and cloudiness 15 and a decrease in light and frequentprecipitation (Kravčík et al. 2007, p. 17-18, 44). All this affectsthe natural water cycle, leads to an increase in urban temperatures andcontributes to other serious problems such as floodings, extreme heatsand droughts (Sass, online). The physical impact of cities on small watercycle might be observed in the figure 19.Fig. 17 The small and large water cycle(Kravčík et al. 2007, p. 20)Fig. 18 Extensive soil sealing in urbanizedareasBuilt surfaces in cities that influence the rainwater runoff have a dramaticimpact on the water cycle (fig. 20). In the table below, we see15 Cloudiness is another important aspect of a biologically well-working small watercycle. The role of clouds, besides inducing rain, is in the absorption and reflectanceof the global sun radiation. Through clouds, the incoming solar radiation isrestrained and hence the earth’s surface heats up less. In urban environments,poor on water bodies and vegetation, the local evaporation of water, and hencealso the creation of clouds in the adjacent atmosphere, is limited. More solarradiation permeates through the atmosphere and heats the earth’s surface up,rising the urban temperature.Fig. 19 The impact of the transformation ofland on the destruction of small water cycles.Rising radiant air flows pushes clouds to coolerenvironments, where the moisturing and thuscooling precipitation falls on earth. (Kravčík etal. 2007, p. 58)2 Literature review: The impact of built structures on climate, energy flow and the water cycle19

the values of water balance of various surfaces. This gives us indirectlythe information about the warming of the adjacent environment. Byvaporization of 1 kg of water at a temperature of 25°C, 2,243.7 kJ ofheat available from solar radiation are consumed (Kravčík et al. 2007,p. 25). On paved areas, where water runs off the surface or infiltratesdeep into the ground, this amount of radiation will be returned into theatmosphere in form of sensible heat. Thus, the lower the evapotranspiration,the higher the heating up of the surface as well as of theadjacent atmospheric layer (see the runoff values in Table 2):a.Table 2. Water balance of variously-used surfaces in mm. 1.1.2001-31.12.2004, TU Wilmersdorf, Berlin. (SenStadt Berlin and TU Berlin, p. 12)intosewageb.Fig. 20 Hydrologic flows in natural environment(a) and changes in hydrologic flows inurbanized catchments with increasing impervioussurface cover (b) and with widely pursuedinfiltration (c) (Göbel et al. 2004; adjusted),showing that mere infiltration provides highgroundwater recharge but has a dramatic effecton the decrease of evaporation rates.c.The aim in urban design should be to lower the runoff values tothe possible minimum and to infiltrate and particularly evaporate(fig. 20a) rainwater on site or as close to the site as possible – bycreating oveground, opened rainwater catchment basins and byenhancing vegetated areas around and on buildings that use therainwater for evapotranspiration and thus achieve energetic balance thatresembles the balance in rural areas (fig. 21).Another of the negative urbanization aspects observed in cities is themodification of natural water streams and ponds – filling in, enclosure(paving-over) or placing in culverts –, drainaging of the wetland surfaceand thus dramatically reducing the evaporative surface of opened waterbodies and adjacent riparian areas (Paul and Meyer in Marzluff et al.,2008, p. 211). The notion thus should be to re-open and restore the naturalstream channels in order to alleviate the urban temperatures. Themore opened water bodies and the greener the city, the higher latentheat partitioning and thus less sensible heat outflow, lowerheat storage and lower UHI effect (Emmanuel 2005, p. 124).Kravčík et al. (2007) warn that the drying of the continents, significantlyaugmented due to urbanization, is receiving very little public or scientificattention. The researchers insist that the water balance at all20Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

levels – even on each city’s territory – must becomea central theme. The understanding of the beyond thecity-scale reaching topic of the significance of the naturalwater cycle is crucial for understanding the need to introducecomprehensive water management practices and todesign with water in cities (Kravčík et al. 2007, p. 79).Designing for rainwater retention and increased evapotranspirationin urban areas to influence the energyflow and water cycle, however, is not the only urban designstrategy to reduce the UHI intensity in cities. Urbanform and geometry, introduced in the following section,are the other crucial themes of urban design to controlurban temperatures.2.3 The impact of urban form and geometryon urban climateFig. 21 Global radiation balance on a greenroof resembles the energetic balance of ruralareas, as in the figure 9. (Schmidt 2010)Besides the elements vegetation and water, in urban areas, the followingdesign-based factors play a decisive role in determining urbanclimate, in particular by influencing the solar radiation absorption andpartitioning through urban form and modified air circulation (Givoni1998, p. 275):• Size of the city• Density and Compactness• Urban geometry: Building height to street width (H/W) ratio, thesky view factor (SVF) and the building volumes• Orientation of the streets (and its impact on insolation)• Ventilation• The particular land useThese factors are introduced one by one in this section, in regard todevelop recommendations applicable in urban design.Size of the cityMany authors declare that there is a clear correlation between the sizeof the city and the UHI intensity in the urban core (Givoni 1998, p. 280,Matzarakis 2001, Oke 1973). Oke (1973) presents a formula for calculatingthe heat island intensity (dT) with the help of population size (P)and the regional wind speed (U), where ‘dT = P1/4 / 4*U1/2’ (Oke inGivoni 1998, p. 281). Emmanuel claims that a threshold for UHI wouldbe a population size of about 1 million people; however acknowledgeingthat this might be difficult to generalize (Emmanuel 2005, p. 26).In some studies, however, the suitability of the population number asan indicator of the UHI intensity is strongly questioned because of otherfactors that determine the city-specific settings; such as the distributionof sealed and landscaped areas throughout the city, building densityand building volume and the release of anthropogenic heat shares(Givoni 1998, p. 281, Oke 1973 in Matzarakis 2001, p. 54-56). For example,the UHI intensity in European cities is, with the same population2 Literature review: The impact of built structures on climate, energy flow and the water cycle21

size, lower than in cities of North America, despite the higher populationdensity. Oke explains this fact with lower anthropogenic energyflows intensity, lower heat capacity of buildings and higher evaporationrate in European cities (Givoni 1998, p. 281; Oke 1973 in Matzarakis2001, p. 54-56) (fig. 22).Fig. 22 The correlation of the UHI intensity andpopulation size for the cities in North America,Western Europe, Japan and Korea (Matzarakis2001, p. 55)We must agree with the authors on the meaning of density andother aspects, such as compactness and land use distributionthat determine urban climate in much higher extent than thesize of a city, either in area or population size. The specific designof an urban area might influence urban climate in bothlarge and small cities.Density and compactnessThe more densely and compactly built is an area, the lower is the exposureof spaces between buildings to solar radiation – and thus thelower the solar heating effect (Ghiaus et al., p. 4). As such, the heatingeffect would be supposed to be more significant in low-density urbanstructures where solar radiation reaches the unobstructed surface ofbuildings and roads easier. In the reality however, higher building densityand compactness often mean lower presence of vegetation andlower wind speed, resulting in higher heat load from heat stored inbuildings 16 , as well as from heat generated by anthropogenic activities17 as in more open areas. All this affects the heat storage in the city,proving that “(…) the higher and denser the built-up areas, the slowerthe rate of nighttime cooling (…)” (Givoni 1998, p. 269).To avoid these heat loads, the density should be kept at moderatelevels, because even cooling measures – such as integrated urban airventilation systems (see ‘Ventilation’ in the section 2.3) and vegetationin the form of green roofs and façades (that do not take over the streetspace and thus do not prevent natural ventilation) – are not sufficientto keep down the temperatures resulting from the exceeding anthropogenicheat loads. The ‘moderate’ level densities, according to the LandUse Plan of Berlin are in the range up to FAR 3.5 (SOI 0.5) 18 . Additionally,according to Mr. Brandl (SenStadt Berlin), areas particularly affectedwith high thermal loads are the areas with high population densities (≥250 dwellers/ha) that have a high ratio of tenants over 65 years andthat lack provision of green open spaces and trees in the street space 19 .Thus, these parameters – the FAR of up to 3.5 and a maximalpopulation density of 250 dwellers/ha – can be considered theupper limits for developments in the moderate climate cities.The bottom limits for urban densities can be determined with the help of16 The 3D, vertical form of man-made, impermeable surfaces means enlarged builtarea that enables higher absorption of solar radiation and its release as sensible(thermal) heat.17 Such as vehicular traffic, air-conditioning, electric devices.18 Applies for mixed-use development (In ‘SenStadt Berlin: Berlin Land Use Plan.Contents and Conventional Signs’, p. 6).19 This information refers to Berlin; assumably might be applicable in other cities.For these types of areas, studies on possible climatic interventions will be madewithin the ‘Stadtentwicklungsplan Klima’ (City Development Plan Climate) programin the upcoming months.22Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

the information that had been given in the section 2.2. The knowledgeabout surface material characteristics in urban areas implies that it isnot only the buildings’ densities, but also the land coverage by pavedsurfaces such as road infrastructure and parking lots, which affects thethermal and climatic conditions in urban areas in a significantly negativeway. Seen from this perspective, there is one unarguably positiveaspect of urban compactness: In compact cities, the ratio of road infrastructure20 to other built-up areas is lower than in sprawled urbansettlements. For illustration, the pro-head area of road infrastructure is24 m 2 when the population density is 50 P/Ha, whereas with a densityof 400 P/ha this is as low as 4 m 2 (Müller and Korda 1999, p. 121) 21 .However, not only the road infrastructure, but also the dispersion ofpopulation – and thus the dispersion of built form – implies that moderate-to higher density developments have a lower pro-head uptake ofclimatically effective land, compared to lower-density, sprawled developments.“The rate of deforestation in the most sprawling metropolitanregions is more than double the rate in the most compact metropolitanregions” (Stone et al. 2010, p. 11); one of the consequences being that“the rate of increase in extreme heat events is higher in sprawling thanin more compact metropolitan regions” (Stone, et al. 2010, p. 10).Fig. 23 Canyon geometry and SVF. Canyongeometry for long streets = height of buildings(H)/ Width of street (W); Sky view factor (SVF)= fraction of sky visible at middle of the street(Emmanuel 2005, p. 23)Therefore, moderate densities are to be preferred to low densitiesto prevent an exceeding uptake of climatically effective land.Additionally, according to the knowledge gained in the section2.2, it should be highlighted that if in moderately dense urbanareas, all roofs and façades were covered by evapotranspirativevegetation, and the rainwater evapotranspiration were allowedin on-site, the natural energy flow and water cycle wouldbe well balanced-out and the impact of the land coverage onthe climate could be minimal. The latter is a finding of high significanceand should be applied in all urban regions, particularly wherehigh land coverage by built structures and high building density areunavoidable.Urban geometryA parameter that to a considerable extent determines the impact ofinsolation on urban climate near the ground is the H/W ratio, the ratioof height (H) of the buildings to the spacing (width – W) between them.The value of this ratio interprets, how much of incident solar radiationreaches the ground, and heats up the air near the ground (fig. 23)(Givoni 1998, p. 247).As shown in the figure 24, in a flat area with H/W ratio “0”, most ofthe insolation is reflected away, or absorbed and later emitted as long-20 Being the only land surface transformed by humans that is not to be possiblybeen greened with vegetation, unlike the buildings’ surface in dense cities.21 This information does not involve the requirements for parking space at drive-infacilities, growing larger with rising dependence on the private transportationmeans. Compact, mixed-use developments thus require not only lower area forroad infrastructure but also for parking space. This is one of the reasons why theheat island intensity is larger in sprawled U.S. cities than in more compact Europeancities (Oke 1973 in Matzarakis 2001, p. 54-56), although the latter havehigher population densities.Fig. 24 Schematic distribution of the impingingsolar radiation in open area with H/W ratio0, in a built-up area with H/W ratio of about1, and in a high-density built-up area with H/Wratio of about 4. (Givoni 1998, p. 248)2 Literature review: The impact of built structures on climate, energy flow and the water cycle23

wave radiation towards the sky. In a medium-density area (H/W ratioof about 1), much of the reflected radiation strikes other buildings orthe ground and is eventually absorbed at and near the ground level. Ina high-density area (with an H/W ratio of about 4 and more), most ofthe absorption takes place high above the ground level. Consequently,the amount of radiation reaching the ground, and heating the air nearthe ground, is smaller than in case of medium or low density. Thiswould imply that the higher H/W ratio, the lower heating of the urbanenvironment.A higher H/W ratio, however, partially restricts the emitting of thestored heat into the atmosphere at night – and thus slows down thenight cooling of the urban environment. Emmanuel (2005) and Matzarakis(2001), for example, are due to this fact convinced that a highH/W ratio significantly contributes to the UHI intensity. For this reason,Emmanuel (2005) and Oke (1988) advocate a H/W ratio of 0.4-0.6in order to trap minimal heat in summer and enhance the trapping inwinter (Emmanuel 2005, p. 39), also satisfying other goals, such aspollution dispersal, solar access, shelter and heat island extent. Emmanuelclaims that although typical central areas in European cities donot conform to the above values (H/W in Europe = 0.75–1.7), comparingthese with the cores of North American cities (where the H/W =1.15–3.3), the compact European cities are still closer to these figuresand thus “more likely to conform to the suggested compatible rangesthan the North American dense cores and scattered suburbs” (Oke,1988 in Raydan and Steemers 2006, p. 22-23).However, a study by Herrmann and Matzarakis (2010, p. 524-525) foran idealized street canyon in Freiburg, a cool moderate-climate city,showed that the most suitable H/W ratio for low temperatures inthe street canyon, given that the street has an East-West orientation,is higher than the values suggested by Emmanuel and Oke – the H/Whas a value of 1.0 and higher. (In case of South-North orientation,the temperatures were generally higher at any H/W ratio.) Despite thetwo deficits of this study: (a) the modellings were made for the periodoutside the summer when the heat wave occurrence is highest and (b)the study did not consider other factors, such as the presence of urbanvegetation and the anthropogenic heat production; this study gives theclearest answers on the appropriate H/W ratio of urban canyons in thecool moderate climate zone.Still, there is a clear controversity of the H/W parameter – on the onehand, the lower the H/W ratio, the higher the insolation and thus streetcanyon heating; on the other hand, the higher the H/W ratio, the lowerthe cooling ability of a street canyon at night. Therefore, an exactstudy should be made for every particular planning situation,and involve the overall density of the area, street orientation,vehicular traffic intensity, buildings’ energy performance andheat exhausts, surface design and greening measures.Fig. 25 The ‘sky view factor’ is equal 1 in caseof unobstructed horizontal area; if a point issurrounded by buildings, it is lower than 1.(Dirk Wolters / KNMI)It can be, for example, assumed, that if the buildings’ surface was coveredwith vegetation, the proportion of the thermal energy consumedby evapotranspiration would be much higher, the impinging solar radiationstored in the construction material and thus the temperature in-24Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

crease lower, the urban geometry parameters would be less significant.Additionally, a cooling effect during the summer months would be expected.Unfortunately, to my knowledge, temperature measurementsof that extent – e.g. covering a street with/and without vegetated builtsurfaces in the same geographic and microclimatic conditions – confirmingthis hypothesis, have not been taken yet.For the above mentioned reasons, we can state that although the urbangeometry is widely acknowledged being one of the most significantfactors determining incoming solar radiation and hence the urban temperaturesand the UHI extent – there is no “right” H/W ratio (orsky view factor – SVF 22 ) generally applicable in all conditions.As such, we could pursue the H/W ratio of 0.4-0.6 advocated by Okeand Emmanuel only if the streetscape wouldn’t consist of dark, impermeablepaving and of buildings built with conventional, heat-absorbingmaterials but would involve sufficient greening measures, low-albedosurfaces and overground rainwater catchment elements. On the otherhand, the streets could be narrower (H/W ratio higher 1) if the coolingeffect of roof- and façade greenery would compensate the exceedinganthropogenic heat loads. In other words, it is the low levels of surfacesealing and greening of open space and buildings that help lower theUHI intensity (and the street orientation and design that supports ventilation,as will be discussed later) in any given urban geometry conditions.The H/W aspect however correlates with the previously discussedaspect of urban density, where certain limits should not be exceeded inorder to avoid too high levels of anthropogenic heat emission.AbsorptionSolar radiationSurface reflectanceSurfacereflectanceFig. 26 Albedo reflection and radiation absorption.In urban environment, the reflectedradiaton will remain within the street profile;being partially reflected but also absorbed byother surfaces. Thus the absorption (and hencelocal surface temperature) will be lower but theoveral radiation (heat) not minimized.The building volumes are another factor determining urban geometry.The larger the surface of buildings, the higher the reflectionrate (multiple reflection of the shortwave radiation, fig. 26) and thehigher absorption of solar radiation and later release in formof heat. Therefore, the volume to surface area ratio of buildings canbe considered having an impact on urban temperatures and climate.Comparing a living area for 10 families, each occupying a 100 m 2 largeliving space in different housing types 23 : (a) one-storey detached, (b)two-storeys row houses, (c) multi-unit building, (d) ten-storey building;the compact multi-unit building proves to be the most preferableone because it has the smallest proportion of walls and roofsand thus is most likely to avoid multiple sunlight reflection and solarradiation absorption, as well as the emmitance of heat from buildingsthrough walls. The highest surface to living area ratio comes in case ofdetached housing (fig. 27).It should be noted that the particular use of buildings – for housingpurposes or as offices etc. – does not have any considerable influenceon the climatic effects of the buildings in general, only their physicalstructure (Zentralinstitut für Raumplanung und Umweltforschung TUM1995).22 The urban geometry may also be expressed by the ‘sky view factor’ (SVF, fig.25). This factor would be equal 1.0 in case of unobstructed horizontal area; “fora point surrounded by close and very high buildings, or for a very narrow street,it may be about 0.1” (Givoni 1998, p. 252).23 Given that the geometry conditions are simplified and the buildings have flatroofs.Fig. 27 The larger the buildings’ surface in urbanareas, the higher the effect of multiple reflectionof short-wave radiation and thus higherabsorption of the solar radiation and its laterrelease in form of heat.Surface calculation of different housing typesthat accomodate ten identical living units á 100m 2 in form of:a) detached houses - total buildings‘ surface2200 m 2b) row houses - total surface 1220 m 2c) units in a multi-storey building (incl. verticalinfrastructure area) - total surface 1140 m 2c) units in a high-rise building (incl. vertical infrastructurearea) - total surface 1370 m 2showed, that a compact, multi-unit buildinghas the smallest proportion of surface to theused space.a)b)c)d)2 Literature review: The impact of built structures on climate, energy flow and the water cycle25

Impact of the street orientation on insolationThe streets’ orientation affects the solar exposure of open areasand buildings as well as the comfort of people walking in the streets.In moderate climates, the objectives on this subject are rather complicated:To provide maximum shade in summer and maximum impingingsolar radiation in the winter. These requirements are difficult to satisfy,as in the summer, the sun stands high on the sky and thus reaches thestreet level easier than in winter, when the radiation angle is considerablylower and the street better protected by buildings from directsolar radiation. There is only deciduous vegetation in form of robust,solar-friendly trees that is able to oblige the human physical comfortdemand, providing shade in summer and letting insolation penetratethrough the thin branches in the winter. In this case, the South-Northorientation of the streets would prove to be most convenient, allowingsunlight reaching the streets’ ground level in the winter.When aiming to alleviate the impacts of the summer heat waves, however,the heating-up effect of the urban canyons must be considered.A study by Herrmann & Matzarakis (2010, p. 525-526) showed that aNorth-South oriented street reaches very high temperatures, while inthe case of East-West oriented urban canyons, the temperatures wereconsiderably lower. 24 Although this study has been conducted on anidealized canyon model, it implies that East-West oriented streetcanyons (and canyons oriented in a small angle to this direction)are optimal in moderate climate. What additionally affects thetemperatures in street canyons is the ventilation, discussed below.VentilationStrong airflow in the streetThe air circulation is essential in mitigation of extremely high temperatures,due to the ability of the wind to transfer cool air from vegetatedareas in the direction of urban cores, pushing the hot air in the centreupwards. Thus, considerable attention will be given to ventilationaspects in this Thesis. The main urban design features that affect thewind conditions are 25 :0 - ca. 10°Fig. 28 Streets parallel or in an small angle (ofup to 10°) to the prevailing wind direction.1.2.3.4.The overall urban density;Combined impact of street orientation and width of the streets;Ventilation channels, open spaces and green shelter belts – theiravailability, size distribution and design details.Height and shape of the individual buildings and the existence ofhigh-rise buildings;Downwind street side with stronger air flowUpwind street side with gentler air flow1. The urban density affects the ventilation conditions in the streets,as well as the potential for natural ventilation of buildings. This effect,however, depends greatly on the details of the urban physical structure.Even in dense urban areas, it is possible to obtain a wide range ofwind conditions by applying different urban design approaches. For ex-The higher street width, the better air circulationFig. 29 Streets oriented oblique to the prevailingwind direction.24 Canyons rotated in between the two main directions showed step-wise modificationin the temperatures, North-South and East-West orientations being the twoextrema.25 Givoni 1998, p. 261; modified and completed26Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

ample, it is better to have an urban area of higher density, witha mixture of high and low buildings, to obtain good ventilationconditions than an area of lower density, with buildings of the sameheight (Givoni 1998, p. 284).The other physical details of urban space that influence the airflowin an urban area more than building density are the orientation ofstreets and buildings with respect to the wind direction and the levelof compactness (Givoni 1998, p. 284), where higher compactnessimplies hindered ventilation.2. Combined impact of street orientation and widthIn the urban environment, different situations emerge according to thestreets’ orientation:Streets free from robust tree vegetation, oriented parallel (or in a smallangle) to the wind direction, create obstacle-free ventilation lanes. Thewider are the streets, the less is the airflow resistance from the buildings,thus improving the urban ventilation (fig. 28) (Givoni 1998, p. 290).When the streets are angled in an oblique wind direction, the windcomponents create different situations in the streets: the first componentflows in the direction of the street, but is concentrated mainlyof the downwind side of the street; the second causes pressure in theupwind side of the buildings. On the upwind side of the street, theairflow is gentler and a low-pressure zone surrounds the building. Thesame rule applies here: the wider the streets, the better the ventilationconditions (fig. 29) (Givoni 1998, p. 290).Streets perpendicular to the wind direction, with buildings of the sameheight, cause the first row of buildings divert the approaching windupwards, making the principal air current flow above the buildings. Therest of the buildings, as well as the streets canyons behind, are in thewind shadow (Givoni 1998, p. 290). Especially in this case it is importantto note, that when the street H/W ratio is higher than 2, the airflow above building height will become highly difficult to reach the pedestrianlevel where the buildings are tightly packed to form a narrowstreet (Kam-Sing et al. 2009). In these circumstances, suitable placementof high-rise buildings creates vertical currents that help stirringthe urban air mass, achieving higher near-ground wind speeds (fig. 30)(Givoni 1998, p. 290, 293).90°“Wind shadow”, ventilation significantly reduced“Wind shadow”, ventilation significantly reducedStrong airflow at the urban edgeCarefully placed higher buildings enhance the air turbulenceon the street level and thus enhance ventilationFig. 30 Streets perpendicular to prevailingwind direction (above - section, middle- ground plan; below - section with adjustedbuilding height).3. Ventilation channels, open spaces and green shelter belts.In the dense city centres, the hot air rises gradually, and a near-ground,cooler air flows from the surrounding lower density areas, green areasor water bodies towards the center (fig. 31) (Givoni 1998, p. 285).The cooling wind masses however can only be transported into thesettlements if there are obstacle-free ventilation channels that enablewind streaming. Already in the 19th century, climate researchers werecalling for wedge-formed open space ventilation systems that wouldprovide ventilation of urban cores (Fritsch 1895).Such ventilation channels can be introduced by urban design to supportthe transfer of cooling air masses between the city center and theoutskirts as well as between the inner city green areas and denselyThe cooling effect ofgreen areas depends onthe presence andcharacter of airflowchannels-°CThe heat island effect is mostsignificant in the urban core+°C+°CFig. 31 Air flow characteristic in urban areasCooling effect 50 -300 m from the bodyof water (depends onthe permeability ofthe built waterfrontand presence ofairflow channels)-°C2 Literature review: The impact of built structures on climate, energy flow and the water cycle27

Emergingof fresh andcold air100-200 mObstacle-freeventilation channelsleading towards theurban coreFig. 32 Wedge-formed open space system thatprovides ventilation of the urban core via ventilationchannels reaching from the outskirts.populated areas. On the level of the whole city, a radial, wedge-formedopen space system is considered being the most effective to providesufficient ventilation (Hahn-Herse 1997, Section ‘Climate’, p. 60) (fig.32). In cities with non-concentric density patterns, the pattern of theUHI and the associated air current are irregular. The topography alsoinfluences the thermally induced air currents (Givoni 1998, p. 285).In these cases, the desired design of the ventilation channels is nonconcentric,adjusted according to given conditions. Within the city itself,these can be open parks free from robust trees, wide avenues orflowing water bodies with little air flow resistance.The ventilation channels are commonly divided into two categories(Matzarakis 2001, p. 220):• Fresh air ventilation channels, producing and transportingpollutant-free “fresh air” that is rich with moisture evaporated fromnatural surfaces and from vegetation (such as grassy, bushy areas,or areas with higher but compact tree vegetation);• Cold air ventilation channels, transporting “cool air” and servingprevailingly to alleviate extreme temperatures (such as linear waterbodies and railways; which both, in contrast to highways causeno or only little pollution loads. Roads, too, may fulfill the cool airtransporting function; however, due to the high load of pollutantsare not categorized as desired ventilation channels.).In this Thesis, the concept of cold and fresh ventilation channels istaken as equal.According to Kuttler, the general features of the ventilation channelsshould be as following (Kuttler in Marzluff 2008, p. 235):• roughness length z < 0.5 mo• zero plane displacement d : negligibleo• length ≥ 1,000 mMa• width ≥ 50 m (depends on lateral obstacles); according to variousinvestigations, a width of 100 – 200 m is, due to its effectiveness,more desirable 26• width of obstacles within the ventilation channel is 2 – 4 times theheight of the lateral obstacles (min. 50 m)a.Mbb.Fig. 33 Ventilation effect of a green space ishindered when surrounded by closed houses’front (a), and better when the building blocksare opened and there are streets leading towardsthe open space (a).• height of obstacles within the ventilation channel ≤ 10mIn compact urban areas however, even a small-scale vertical circulationbetween residential block and adjacent green space proves effective(Andritzky and Spitzer 1981). The depth of the cold air penetratingfrom these local circulations into the built environment is however determinedby both the design of a green area and by the form of thesurrounding buildings. If for example a green area is in a depression orsurrounded by a wall, the air exchange is hindered and thus the penetrationdepth reduced; or, if a green area is surrounded by closed, highhouses' front, the climate meliorating effect is confined to the immediatevicinity (fig. 33a), as proven in the Tempelhof Study (Appendix4). Conversely, in a loose building structure, with open building blocks26 SenStadt Berlin and BSM 2009, p. 46; Mayer and Matzarakis 199228Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

and streets leading towards the green areas, a deep penetration of airinto the built-up area is possible (fig. 33b) (Sukopp and Wittig 1998, p.158). Presented on real case studies, the shape of urban blocks aroundthe Park Volkspark Friedrichshain in Berlin (fig. 34) will provide betterventilation beyond the urban edge of the park than it is in the case ofcentral Park in Nye York (fig. 35).Furthermore, the type and density of trees have a noticeable impact onthe airflow near the ground. A densely planted ‘shelter belt’ may obstructthe airflow and, if desired, provide a good protection from wind;however, it can also direct the wind to a desired spot, for example to anopening serving as an inlet for ventilating a building as in the figure 36.(Givoni 1998, p. 307). This so called ‘shelter effect’ can be achievedwith help of buildings, too: gradually ascending buildings may pointwinds above a dense area and provide turbulent ventilation in areasbehind the front line of buildings (fig. 37).Fig. 34 Partially opened block structure aroundthe park Volkspark Friedrichshain in Berlin enablesventilation of the urban areas (Google).4. Height and shape of the individual buildingsThe principal factors which determine the urban density effect on theurban ventilation conditions are the average height of buildings andthe distance between them; the differences in the heights of neighbouringbuildings being particularly decisive (Givoni 1998, p. 282). Individualbuildings rising appreciably above other buildings create strongair currents in the area and can modify the wind flow pattern and thewind speed at the pedestrian level (Givoni 1998, p. 285, 293). The effectof the high-rise buildings on the urban wind field however dependsgreatly upon their specific locations within the urban fabric; if desired,the high-rise buildings can block the wind and reduce significantly thewind speed in the urban area as a whole (Givoni 1998, p. 293-294). Ingeneral, high concentration of tall buildings in a dense city center andcommercial areas reduces the wind velocity and thus the cooling effectnear ground level, unless the street canyons between buildings arealigned with the wind direction (Sass, online). The denser the urbanarea and the higher the buildings along the streets, the stronger theeffects of buildings on the local wind patterns and wind strength.On the other hand, solitary high-rise buildings with large open spacesbetween them have better ventilation conditions than closely spacedlow buildings (Givoni 1998, p. 294-295). In case of solitary high buildingshowever, an attention must be paid to the overheating, resultingfrom the high solar exposure.The flow pattern around high-rise buildings depends on the followingfactors:Fig. 35 High, enclosed buildings’ front at theCentral Park in New York hinders ventilation in penetrationbehind the urban edge. (Free photos)HFig. 36 Thoughtful planting of vegetation ofcertain height may steer winds entering openingsin buildings, where ventilation is desired.1. The building’s own H/W ratio as well as the wind direction withrespect to the façades of the building. The wider the windward sideof the high-rise building, the stronger the emerging air currents inthe area, with high-pressure downward currents along the façade.2. Whether the upwind façade is flat, concave or convex. Aconvex wall diverts more air to the sides and less upward and downward.It smooths the deflection of the flow and therefore reducesthe resulting turbulence at the side wall and at the windward wall.Fig. 37 Shelter effect (Gandemer 1975 in ZRUTUM, p. 244)2 Literature review: The impact of built structures on climate, energy flow and the water cycle29

a. b.On the other hand, a concave windward wall concentrates the flowalong this wall, upward and downward, increasing the turbulence.Setback of thetower of a high-risebuilding orhorizontal façadeprojections reducedownflow of thewind and minimizesnon-desiredturbulences on thestreet level causedby the high-risebuilding6-10 mSetbackof thetowerHorizontal façade projections3. Specific design details of the building itself. A setback of thetower, with respect to its base, starting about 6-10 m above streetlevel, can eliminate most of the downflow at the street, where theturbulence affects the pedestrians (fig. 38a). Such a design solutionstill maintains the positive effect on the mixing of the streetlevelpolluted air with the clearer air from above (Givoni 1998, p.297-298). Similar effect have horizontal projections on the façade,such as shading overhangs (fig. 38b) (Arens 1982, Givoni 1998, p.297).Fig. 38 Setback of the tower of a high-risebuilding or horizontal façade projections reducedownflow of the wind and minimizes nondesiredturbulences on the street level causedby the high-rise buildingAnother point to note is that one comparative study of ventilation instreet canyons with flat and with pitched roofs pointed out that theshape of roofs also has an influence on ventilation conditions in thestreets. The study showed that “pitched roofs cause recirculation of airnear roof level, hence reducing wind speeds at street level and causingpoorer ventilation (Barlow 2006).” Thus, for desired intensity ofventilation, flat roofs are to be favoured. 27Summarizing the above considerations and knowledge on ventilationin urban areas, the difficulty in suggesting an urban form that wouldmake the most efficient use of wind flows in moderate climate cities –providing sufficient ventilation on one hand and human physical comfortthroughout the year on the other hand 28 – becomes evident.Yet, it seems likely that a mid- to high density urban form, withstreets possibly angled in parallel direction of the wind (or ina small angle to the direction of prevailing winds), and, whereneeded, with a few thoughtfully placed high-rise buildings thatcause stirring up of the wind masses on the street level, wouldprovide sufficient ventilation while preventing street canyonsfrom overradiation. Additional ventilation channels reachingfrom the urban outskirts into the urban core as well as localventilation channels between inner-city green areas and waterbodies will provide ventilation and cold air transfer on the levelof the whole city.It is also important to note, that whether the ventilation designing strategiesaim for significant wind streaming or against it, light winds are alwaysdesirable in the streets and open spaces, to mitigate the effect of solarheating (Givoni 1998, p. 289) and of the anthropogenic heat release.27 Flat roofs also have an advantage of easy installation of green roofs in combinationwith photovoltaic panels. Roof vegetation cools the air in the proximity of thephotovoltaic system and thus enhances its efficiency and energy yields (Köhler etal. 2002, p. 157).28 The desirability of higher or lower wind speeds in moderate climate zone dependon the given season. In general, in summer months, ventilation and sunprotection are desired – in winter, unobstructed insolation and protection fromwinds. These requirements are difficult to fulfill, because, for example, if vegetationsuch as robust deciduous trees is used, desired shading in summer will beachieved – but also ventilation obstruction due to the thick treetops. On the otherhand, bare tree skelets allowing sunlight in the winter don‘t protect against thewind. These controversial aspects are to be considered and weighted in everyspecific planning situation.30Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

2.4 The effects of land use on urban climateThe character of land use significantly determines the energy balance incities. According to the surface design and urban geometry in given typesof urban areas, these may be predetermined to have climatically positiveor negative character (compensation areas or impact areas).These are on the one hand the cold air-producing space, characterizedby vegetation or water (parks, rivers and lakes) and the bio-climateand/or air-quality burdened settlement areas (dense urban cores,closed urban block developments, industrial areas) on the other hand.These spaces can be connected by linearly aligned open spaces (ventilationchannels) (Environmental Atlas Berlin – Climate, online). Abrief introduction to various urban land use forms and their general,climate-related description is given in the Appendix 1.Particular attention in this section will be given to the climatic functionsof two land use categories that play a significant role in mitigation ofthe high temperatures in cities: to water bodies and vegetation. Theclimatic effects of these categories are being widely underestimated inurban design processes, considering the fact that they can be easilyimplemented not only in the design of open space, but also as a partof building design – this even in densely built urban cores. Despite thisknowledge, the integration of water and vegetation is being widely neglectedin dense cities and low-cost, artificial built structures are beingfavoured in most developments.Water in urban design – Water bodiesAs discussed in chapter 2.3, water bodies are excellent absorber of radiantenergy (heat), using the solar energy as well as the sensible heatrelieved from the built-up area for evaporation and thus creating an“oasis effect”. Additionally, in overheated urban areas, the warm air risesabove the settlement and the cold air moves due to the air pressureclose to the ground from the adjacent cooler water body in the directionof the built-up area (Sukopp and Wittig 1998, p. 161) (fig. 39).The extent of the temperature decrease depends mainly on the widthof the roads or open spaces leading towards water. A measurementconducted in Japan showed that in a 100 m wide open space thatruns perpendicular to a river, a temperature reduction induced by thewater of about 2°C is significant at a distance of 50 m from the shore.Even after 300 m, a temperature lower by 1°C was measured. Narrowerstreets lead to lower impact (Sukopp and Wittig 1998, p. 162).The temperature sink effect is more significant in case of predominant“river winds”, with the flow direction into the built-up area (Sukopp andWittig 1998, p. 162).In concrete embankments, the cooling effect of rivers is of significantlyshorter distance. A study by Murakawa et al. (1998) demonstrated thatthe presence of a 4.3 m high embankment caused that the temperaturelowering effect of the built-up area was within its range by about70 meters shorter (!) (Sukopp and Wittig 1998, p. 162). This situationis similar in Berlin, with very high rate of embanked rivers (fig. 40).+°C-°C-°CFig. 39 Basic principles of the thermal effectof a water body in an urban areaFig. 40 High river embankments hinder coolingwinds from the river channels enter the settlement+°C2 Literature review: The impact of built structures on climate, energy flow and the water cycle31

a.b.-°C-°C50-300 m-°CNot only temperature decrease, but also the increase in air humidity 29can be measured in the proximity of water bodies in urban areas. Itwas observed that changes of the relative humidity in densely built-upareas are evident up to 50 m. In areas that are less densely developed,this influence may be up to 150 m. When building complexes are looselyarranged, and their long axes are perpendicular to the water’s edge,a particularly favorable distribution of the air humidity is possible. Inthis case, the influence of up to 300 m wide range in the cultivatedarea, producing humidity raise of up to 5% (Sukopp and Wittig 1998,p. 162) (fig. 41a,b).Fig. 41 Perpendicular orientation of the buildings’long axes to the water body enables freshair and humidity permeate into the settlement.The cooling effect of the water body and raisingthe humidity range up to 300 m (in dense areasthe positive climatic influence of the water bodyis about 50 m) (a).To raise the density and take the highest advantageof the water location, buildings’ abovethe ground might be built in a permeable way(b).Thus, the larger and the shallower the riparian, natural-like wateredge areas, the better – for both evaporation (which has theeffects of cooling and rising the air humidity) and ventilation. Additionally,enlarging of the water surface area and its interweavingwith the built-up areas is the best design way, since the climaticeffect is claimed to be highest where the built-up area meets the waterbody’s edge (Song 2003, p. 68).Vegetation in urban design – Parks and greenareasThe climatic effects of urban green in cities are in improving the airquality and urban climate through the retention, absorption and evapotranspirationof rainwater; returning the rainwater in form of vapourto the small water cycle; reducing air pollution; reducing the noiseimpact by traffic, neighbours, etc.; positively affecting natural urbanventilation; and providing urban areas with shade and lower temperaturesin hot seasons.However, obviously, in estimating the extent of the positive effects onclimate, there is a need for clarification of two questions (Sukopp andWittig 1998, p. 158):• What size and character must a green space have in order to improvethe climatic situation in the adjacent built-up environment?• Up to what distance from the green space can a positive influenceon the climate in the built-up area be demonstrated?Brief answers to these questions deliver the results of a study concernedwith five green spaces and ruderal areas of different sizes inBerlin. The study determined the range 30 of the climatic effects of thesegreen areas. The greatest effects could be observed on the lee sideof the green spaces. It has been proved that the amplitude of greenspace also plays a significant role – the larger, the greater is the climatologicalrange. The “Großer Garden” features an effect of temperaturereductions up to 1,500 m on the leeward side. However, even againstthe wind direction, on the windward side, the green space can haveclimatic effects up to a depth of 200 m in direction of the built-uparea. (Sukopp and Wittig 1998, p. 159) Here, urban green ventilation29 As brought up in the section 2.2, higher air humidity implies lower UHI effect.30 ‘Range’ meaning the distance from the edge of the green space into the builtuparea, where the minimum temperature difference is 0.5°C, compared to theadjacent urban environment.32Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

channels play a role of distributors of the cooler, fresher air into theadjacent, densely built urban area. The loose design of the “urban”edge (the building line on the border with urban park or open space) isof significant importance, too – in allowing the penetration of coolingwinds into the built-up area (fig. 42).It is however important to note that the positive climatic effects ofurban green areas should not be kept to the areas primarily devotedto recreational function, such as parks and gardens. The temperaturelowering potential of small green urban patches in form of vegetationon and within buildings is immense (fig. 43), and should be taken advantageof, especially in densely built urban areas.Cool air impinging from the urbanpark thanks to permeable urban edgeCompact urban edge prevents coolingair entering the closed urban blocksand hinders natural ventilationTo illustrate this statement, the climatic effects of buildings’ greeningmeasures (in this case green roofs) applied at the large-scale, wholecity level, have been estimated in the Toronto studies of green roofbenefits. The first study, taken in 2002, states that “using 6% greenroof coverage over 10 years (representing only 1% of Toronto’stotal land area) could result in an average overall reduction of1°C in the urban heat island effect, with a reduction of as muchas 2°C in some areas” (Urbis Limited 2007, p. 15-16). A complementingstudy on the potential environmental benefits of widespreadimplementation of green roofs in the City of Toronto (2004; Appendix3) indicated that citywide implementation of green roofs in Torontowould provide significant economic benefits to the City, particularly inthe areas of stormwater management and reducing the UHI (and theenergy use associated therewith) (Banting et al. 2005).Local aircirculationFig. 42 Loose design of the building line onthe border with an urban park or open space(below) is important for wind dispersion intothe urban area.Studies like these point out that even buildings’ greening in dense urbanareas, if applied city-wide, can have a considerably positive effecton urban climate; and suggest reconsideration of the in urbanplanning common land use categorization into “green space”and “built-up areas”.Fig. 43 High temperatures in case of an urbanizedarea (above) and the temperaturelowering effect of an extensive green roof (below)(Wong and Chen 2009).2 Literature review: The impact of built structures on climate, energy flow and the water cycle33

2.5 Literature review: Lessons learnedAs the character of the natural landscape changes in the urbanizationprocess, the energy exchange with the atmosphere and the water cycleare affected – and hence the microscale, mesoscale and even the macroscaleclimate is modified. These aspects are additionally influencedby the urban form (morphology), with the ability to milden or exaggeratethe one or another thermal/climatic aspect.The aim of this section has been to point out that both surface characteristicsand urban geometry in the built environment are importantmatters and that we – urban designers, planners, architects, and otherstakeholders involved in city design – must learn from the natural conditionsin regards to the mitigation of the UHI effect when planning andbuilding cities.In this section, we learned that when aiming for the mitigation of theUHI effects and of extreme heat events, what really matters in urbanclimatic considerations are the following elements and their interaction:• Urban form – in particular the density/compactness and geometry– as a factor affecting insolation, ventilation and storage heatemission;• Ventilation – that enables air circulation between the cooler areas(green spaces, water bodies) and the hot urban areas, and thusprovides the hotter areas with cool air;• Solar radiation – transformed into latent heat in the process ofevapotranspiration and shaded by particular design of urban formand geometry;• Water and Vegetation – in particular their effects on loweringurban temperatures via evapotranspiration.The interaction of these elements that supports natural energeticprocesses must be well thought of and applied in urban design (fig.44). This implies that one condition for tackling the worsening climaticconditions in cities is the renewal of the basic ecological functions,which are closely connected with the return of water and vegetationto the urban environment. As explained on the example of the smallwater cycle, the necessity of the functional renewal does not only referto non-urbanized regions; it should be widely applied at the city’sand each building’s level, too!On the local (micro- and mesoclimate) level, other discussed measures– such as albedo changes of road surface or adjusting of urbangeometry – might be of use. However, it must be remembered: theevapotranspiration is the only way, where the solar energy“dissolves”, not being reflected back into the atmosphere ortransformed into sensible heat. 31 This is a rather “new” recognition31 Measurements taken on two green roofs in Berlin showed that 58% of the radiationbalance can be converted into evapotranspiration during summer months(Senstadt Berlin and TU Berlin 2010, p. 16). In a typical urban street profile witha H/W ratio 0.9 it is only 10% energy for water evaporation! (According to astudy conducted by Oke 1981 in Givoni 1998, p. 247)34Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

in urban design, yet not being commonly applied. It indicates that theinteraction of natural elements, in particular of air, water, soils andvegetation must be enabled. Only when providing air- and waterpermeable surfaces, connected to vegetation, the urban heatisland can be mitigated at the district level. This requires a dramaticsoil sealing reduction and greening of all man-made surfaces,in particular of roofs and walls.The Thesis’ knowledge base is on the above mentioned findings, withthe aim to compose a set of complementary methods that would contributeto mitigation of extreme weather events in moderate climatecities.The Thesis is also trying to point out, that the application of thesemethods might not only have local effects, at the level of a singlestreet, urban block or a city. More than that, with sensible managementof water and vegetation across larger urban areas, perhaps thismight have an effect of tempering energy flows and water cycle on abigger scale, with positive effects on regional and possibly even onglobal climate.1.-°C-°CFig. 44 Schematic diagram comparing thebasic energy and water cycle characteristicsof the natural environment (1) and the urbanenvironment (2). Image (3) suggests urbandesign implications according to the findings inthe literature review:a. Provide air flow channels from the outskirts;2.-°C+°C+°C-°Ch.b. Build ventilation lanes in the city;c. Green roofs and façades of buildings to supportevapotranspiration;d. Induce local turbulent ventilation by correctplacement of high rise buildings;e. Pave surfaces with pervious materials;f. Design high albedo surfaces of buildings andpavements;3.-°Ca.b.-°Cc.d.-°Cf. f.e.g.-°Ch.g. Allow ventilation channels transport cool airfrom rivers;h. Take advantage of the river air flow channel.Reflections on the researched topicAlthough being able to estimate the effects of the one or another meanto mitigate the temperature extremes, large-scale measurements andstudies on climatic aspects of the proposed methods, done by scientists,are still lacking. These are, for example, measurements of effectson an urban district if, for instance, turning all roofs and façadesgreen and/or affecting the overall geometry or the albedo of the district.Therefore, we nowadays need to rely on assumptions based onsmall-scale measurements and rough estimations.2 Literature review: The impact of built structures on climate, energy flow and the water cycle35

3 Climate-Sensitive Urban Design(CSUD) in moderate climate zone“Poor urban design is the biggest cause of the heat islands in our cities”(Larry West in EnvironmentAbout, online).We therefore need to reinforce the thoroughly understood way of Climate-SensitiveUrban Design (CSUD) – a comprehensive way of designingour cities while skilfully combining all possible means.As demonstrated in the section 2, significant research has been doneon urban climate and on effects of the urban heat island and on howthese can be mitigated. Thus, when addressing the UHI mitigation incities, these findings are of considerable importance. According to thefindings, a combination of measures in the below mentioned areas ofintervention should be applied in urban design 32 :• Urban form – in particular, density/compactness and geometry– That allows proper rate of insolation/shading, ventilation andallowing space for vegetation;• Natural ventilation – Taking advantage of existing and creatingnew ventilation channels; creating air-permeable buildings andbuilding complexes (the latter with the help of urban geometryadjustments), for balancing-out the “urban” heat with provision ofcool air;• Solar radiation – Transforming the incoming solar radiation intolatent heat with the help of water and vegetation; shade provision;application of high albedo materials to prevent heating up ofsurfaces (as a measure of secondary priority);• Natural water cycle – Total reduction of rainwater run-off throughintroducing decentralized rainwater management whose primaryfocus is on rainwater evaporation on site by creating water permeable,preferably vegetated surfaces as well as by enhancing thepresence of water bodies;• Vegetation – Enhanced greening of cities, in particular greening ofbuildings and extensively used man-made surfaces to enhance theevapotranspiration rates.As such, Climate-Sensitive Urban Design aims at the combination ofvarious elements that mitigate the UHI effects. The design is to involvestreet profiles, building orientations and appropriate urban densityand compactness, which provide adequate geometry for shadingand natural ventilation of streetscapes and buildings and thus alleviatethe anthropogenic heat loads. The urban form arrangements are to becombined with the decentralized overground rainwater management,water bodies, green roofs, podium gardens, balcony/terrace gardens,façade greenery, street plantings (trees and vegetated swales), fore-32 For the purpose of this Thesis, the design of the buildings (which, for example,influences the requirements for heating and air-conditioning) will be avoidedin detailed considerations. The Thesis focuses on the beyond-a-single-buildingreachingurban design level, and on landscaping features.36Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

gardens and any other possible means of greening cities, and with the(re-)creation of natural-like, air- and water-permeable surfaces.The particular detailed design recommendations will be introducedin the section 3.2 in a set of Climate-Sensitive Urban Design (CSUD)Guidelines and later on applied in the climate responsive model urbanarea Europacity/Heidestrasse.3.1 Review of existing CSUD guidelinesBased on the knowledge about the effects of the physical built structuresand built form on urban climate, presented in Section 2, existinggraphic and written guidelines have been reviewed, looking for thepresence of the components of Climate-Sensitive Urban Design (seealso section 3.2). Regrettably, there is yet no comprehensive set ofguidelines available, which would address all the desired areas of interventionin urban design: solar radiation, small water cycle, vegetation,urban form and geometry and natural ventilation.As previously mentioned, the literature sources on climatic urban designguidelines – Givoni (1998) and Emmanuel (2005) only bring designguidelines for tropical and cold climates; and primarily refer tourban form and geometry, not paying sufficient attention to the otheraspects.Therefore, there is a need to reach for municipal guidelines and documents.The guidelines from municipalities in various countries, althoughnot explicitly addressing the topic of ‘Climate-Sensitive UrbanDesign’, nonetheless bring valuable information, e.g. the “StormwaterBest Management Practices” for Chicago, the NYC’s “High PerformanceInfrastructure Guidelines” or the Berlin’s “Rainwater management concepts.Greening buildings, cooling buildings. Planning, Construction,Operation and Maintenance guidelines”. These guidelines, briefly introducedbelow, have an advantage of addressing specific planning conditions,and hence being of great use for local planning communities; onthe other hand, they, again, refer to small-scale, mostly open-spacerelated measures and avoid urban form and geometry, as an importanttool for achieving the proper ratio in incoming solar radiation, shadingand ventilation. The reason for this might be the difficulty of inventinggenerally applicable guidelines that address urban form and geometry,given the complexity of the factors that need to be considered and thatvary in any specific conditions, such as the regional winds’ speed anddirection.The Chicago’s “Guide to Stormwater Best Management Practices”(2003) provides a thorough set of recommendations on stormwatermanagement. The guidelines do not mention the relation to climate; therainwater evaporation however, as we learned previously, is the mosteffective way to tackle the urban climate problematics with the helpof urban design. The guidelines discuss design means such as greenroofs, permeable paving, natural landscaping, filter strips, bioinfiltrationin rain gardens, drainage swales and naturalized detention basins; allof them being effective in reducing the quantity of stormwater runoff.The design recommendations for the CSUD Heidestrasse/Europacity,Fig. 45 The Chicago’s Guide to StormwaterBest Management Practices3 Climate Sensitive Urban Design (CSUD) in moderate climate zone37

ought in the section 3.4, are mainly inspired by these guidelines.Fig. 46 NYC’s High Performance InfrastructureGuidelinesThe NYC’s “High Performance Infrastructure Guidelines” (2005)have a broader area of interest, focusing on public open space (e.g.albedo rising on streets, cycle ways and sidewalks). Besides being verythorough and covering a high range of climate-related urban design issues(pavement, stormwater management, landscaping), they do alsobring quantitative statements and recommendations. The quantificationrefers to particular planning aims and objectives, like e.g. statingperformance goals: “Achieve an albedo of 0.3 or higher on road resurfacingand reconstruction projects (p. 82)” or “Seek to capture, retain,treat, and facilitate either infiltration or evapotranspiration of all smallstorms, or 90% of average annual storm runoff volume (p. 125).” Dueto the quantifying character, these guidelines are an inspirative sourcefor determining the extent of measures applied in urban design.Berlin’s documents addressing CSUDFor reviewing the recommendations by the city where this Thesis’ casestudy area, Heidestrasse/Europacity, is situated, closer attention ispaid to the urban design and planning regulations introduced by theCity of Berlin. The investigation showed that Berlin’s regulations havevaluable provisions for addressing the UHI effect as a general policy toadapt to climate change:• Guidelines “Konzepte der Regenwasserbewirtschaftung”(“Rainwater management Concepts. Greening buildings,cooling buildings” Guidelines, 2010) – Thoroughly discussing theenergy flows and water issues and their relevance in urban design;Aiming at decentralized rainwater management, greening of buildingsand building cooling based on non-conventional adiabaticcooling technology, that uses (rain)water. These guidelines, too,are an inspirative source for the design recommendations for theCSUD Heidestrasse/Europacity;• “Planungshinweise Klima” (Planning Advices Urban Climate, Map4.11.2 in the Environmental Atlas Berlin – advisory documenthelping boroughs decide about permissibility of developmentproposals)• “Stadtentwicklungsplan Klima” (City Development Plan Climate) –yet unpublished, city-wide planning document, aims at the largerscaleplanning (1:100,000 to 1:20,000); particularly at the spatialallocation of the climatic impact and compensation areas and ofventilation channels of the whole-city significance.Fig. 47 Berlin’s Rainwater Management ConceptsGuidelines.• Remarkably, the planning law, e.g. the “Klimaschutzgesetz –Entwurf” (Climate Protection Law – Draft), despite the knowledgeand awareness at the city’s planning level, only aims at the carbonproblematic and introduction of renewable energies and fully avoidsthe physical impacts of land use and of construction materials andthe urban form.According to the talks with consulted professionals 33 , the principal climate-relatedpriorities in Berlin’s urban development are (a) Land use33 Mr. Andre Heinzel (SenStadt Berlin), Mr. Heinz Brandl (SenStadt Berlin)38Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

eduction through land recycling; (b) Albedo rising; (c) Buildings’ andopen space greening, pursued in renewal projects as well as in new developments;(d) Decentralized rainwater management; and (e) Spatialform that takes an important position in planning – in particular theconcepts of ventilation channels that connect climatic impact areas andcompensation areas (Environmental Atlas Berlin – Climate).A powerful mean to enhance greening is the “Biotopflächenfaktor”(‘BFF’; “Biotope Area Factor (BAF)”, Appendix 3). Because of the categorizationof built areas, the BAF does not require all developmentsto be to a high extent vegetated, but it makes the calculation easierfor particular development types. Additionally, the document “EcologicalConstruction – Requirements for Construction Projects – Guidelines“ (2007) states inter alia “Conceptions of greening real propertiesand buildings shall comprise specifics of how to use storm water andground water. In inner-city areas in particular, the option of greeningfacades and roofs shall be looked at.” (SenStadt 2007, p. 15)Although there is no general information and/or guidelines availableon urban form and geometry, there are climatic studies that have beenconducted for strategic development projects in Berlin – in particular,the climatic study for the former Airport area Berlin-Tempelhof 34 . Thisstudy, introduced in Appendix 4, provides valuable information applicableto other developments, even to the case study of this Thesis,Heidestrasse/Europacity, and is the only available document that addressesBerlin’s urban form and density.A critic is that despite the climate-responsive notion, recently pursuedin Berlin’s city planning, masterplans and local development plans(“Bebauungspläne”) are being designed in a similar way as they hadbeen in the past. “Even the as particularly climate-responsive claimedproject for Heidestrasse/Europacity is based on the usual design andperformance principles” (Mr. Heinzel, SenStadt). This can be attributedto the facts that no guidelines address urban form, and that theexisting guidelines that cover other issues only have a recommendingcharacter – meaning, none of the heat island reducing measures iscompulsory.Yet another reason might be associated with the lack of a thorough setof guidelines that would exclusively address the UHI reduction. The aimof the next section thus is to provide such a set of guidelines.34 SenStadt Berlin and BSM 20093 Climate Sensitive Urban Design (CSUD) in moderate climate zone39

3.2 Proposed CSUD GuidelinesThe set of Climate-Sensitive Urban Design (CSUD) Guidelines, aimingto alleviate the UHI in cities and to mitigate the effects of the extremeheat events, presents particular detailed design recommendations inthe following categories:Urban form – density/compactness and geometryVentilationSolar radiationWater cycle and VegetationSpecial design details of buildings affecting outdoor conditionsGeneral recommendationsUrban form – density/compactness and geometryFig. 48 High density settlements have a veryhigh storage heat and anthropogenic heat loadrelease. Is a dense urban district such as theone pictured (Hackescher Höfe, FAR 4.0) likelynot to contribute to the UHI, even when all otherdiscussed design UHI mitigation means willbe implemented? (SenStadt 2005, p. 6; © FTBWerbefotografie)Although many authors consider high density as a factor critically contributingto the UHI effect (e.g. Matzarakis 2001, Emmanuel 2008),the conclusions about the “right” densities to tackle the UHI effectsare rather controvensial. The complexity of the given subject makesthe estimation of the “most suitable” density, compactness, buildingvolumes, as well as the street geometry practically impossible. Fot this,it is necessary to examine also the aspects such as the evaporativecooling rates 35 , ventilation loads, albedo effect etc. for every particularplanning situation. The energetic output of these factors would needto balance out the heat loads in an urban area caused not only by theincoming solar radiation, but also by other forms of heat produced bythe district – such as the heat from electric devices and vehicular traffic(fig. 48). These estimations present a very complex set of issues andare not possibly to be determined within the frame of this Thesis; neverthelessshould be considered if a planned district is not to contributeto the UHI of the whole city.According to the findings in the section 2.3, we can neverthelessroughly derive following recommendations:Density• Do not exceed average urban density of FAR 3.5 (SOI 0.5) andthe population density of 250 P/ha.• Avoid sprawled developments that consume vast areas of climati-cally effective land.Urban geometry• Plan for about six storey average 36 building height and correspondingstreet profile of about 19 m width (the “European35 See Institute of Physics, Appendix 5.36 “Average height” allows, and in most cases even demands, alteration within thedevelopment, meaning lower buildings and looser urban form on the edge of thedevelopment – in the proximity of ventilation channels; the density and building’height increasing towards the core of the development.40Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

City” compact typology, a H/W ratio of about 1 and higher). Thisshould allow for sufficient shading by buildings as well as ventilation;presumed there are other design means implemented to alleviatethe heat extent simultaneously, such as presence of vegetationand water elements in the streetscape and on buildings.Vegetated areasand water bodies(emerging of freshand cold air)100-200 m• Orientate the streets in the East-West direction to achieve thebest cooling effect and thus lowest temperatures.VentilationUrban areas100-200 mFig. 49 City-wide ventilation channelsObstacle-free air flowchannels in the directionof prevailing windsVentilation channels• Secure and develop city-wide, large-scale, pollutant-freeventilation systems that include regions of cold air formationand barrier-free ventilation channels reaching from the edge of thesettlement well into the urban center; such as green open spaces,rivers or railroutes (fig. 49).• Interconnect ventilation channels with vegetated areas orwater bodies to increase their effectiveness in transfering coolingwind streams. The ventilation channels should be about 100-200 mwide and correlate with the direction of prevailing winds (althoughin the urban areas, the “high pressure climatic conditions” mostlysuffice).• Design the ventilation channels in dense urban areas as linearorientedopen spaces; for being effective, their width should not bebelow 50 m (fig. 50).• Improve the permeability of the urban fabric: Where the coldand fresh air is desired to enter the settlement to provide betterventilation, the settlement edges cannot be closed (fig. 51a). Thisimplies to avoid closed urban blocks as well as dense tree andshrub vegetation. Favourable are smaller buildings’ dimensionsand larger distances between the buildings. 37Fig. 50 Ventilation channels in urban areas aslinear-oriented open spacesa.• Where desired, the urban edge adjacent to the ventilationchannel might be closed to steer the windflow and enhance itsspeed (fig. 51b).• Adjust buildings near the ventilation channels in height anddimension; they should not reach considerably above the averagetree height.• Avoid plantations with high-growing trees, for examplepoplars, in and besides ventilation channels.b.• Use the “shelter effect” (gradually rising heights of buildings,possibly combined with tree vegetation) where the buildings’ edgeof the settlement is impermeable to provide ventilation in areaslocated in a larger distance from ventilation channel.• Make water edges shallow, never built them up. The cooling37 The design of open edges of settlement however is not to be confused with theurban sprawl and uptake of new open land areas. The purpose is to loosen theedges of settlements to make it wind-permeable, not to expand the urbanizedarea (Hahn-Herse 1997, Section ‘Climate’, p. 65).Fig. 51 Design of the urban edge either allowsthe winds penetrate and provide the settlementwith ventilation (a) or steers the winds withinthe stacle-free air flow channelschannel, not allowingto enter the settlement (b).3 Climate Sensitive Urban Design (CSUD) in moderate climate zone41

effect of a water body reaches into considerably higher distancecompared to the of an enclosed water body (Sukopp and Wittig1998, p. 162).Local air circulationFig. 52 Extended access balconies that connectsingle-standing buildings allow ventilationwhile creating a “compact urban block” structure,Bozen, South Tyrol (www.provincia.bz.it)• Support autochtonous local air circulation within a singlebuilding block and the adjacent open space, where no superiorventilation channels are present. For this, wind permeability ofbuilding blocks is to be provided (fig. 42).• Open buildings and urban blocks to provide ventilation indense urban areas. Involve extended access balconies connectingsingle standing buildings instead of built corners (fig. 52), andopenings in buildings and in urban blocks (fig. 53) to enhancelocal air circulation 38 where a solid, compact urban block structureis required (such as in dense urban cores).• Involve architecture on stilts to enhance the near-ground ventilation(besides enhancing evapotranspirative ground area) (fig. 54);Street ventilation• Orientate streets parallel to wind direction (or in a small angle)to optimize wind flow and thus aid in cooling that area of the city.Fig. 53 Openings in compact urban blocks forbetter air circulation• Widen streets to support turbulent ventilation where higherwind speed is desired (unless oriented in the prevailing wind direction,where the wind speed is higher and thus a narrower streetprofile suffices). To lover the pollution loads in the streets, it isrecommended to provide these with pollutant-absorbing façade- orhigh tree vegetation.• Take advantage of the venturi-effect – design open spaces triangle-liketo enhance wind speeds.• Use façade greening instead of tall trees in the streets wherestrong ventilation effect is desired (Wong and Chen 2009, p. 32).However, use robust tree vegetation where wind blocking isdesired, for instance in pedestrian areas (Givoni 1998, p. 297).• Involve flat roofs to enhance ventilation at the street level (fig.55).Fig. 54 Architecture on stilts enables betterventilation near the ground and enhances thepervious areaSolar radiationTransform incoming solar radiation into latent heat as themain priority• via evapotranspiration of water, see ‘Water cycle and Vegetation’.Albedo• Reduce local surface temperatures through the use of reflective andlight-coloured (high albedo) surfaces;• Apply the albedo measure additionally to greening means, at spotswhere vegetating is not possible (such as in case of roads and side-Fig. 55 Flat roofs enhance ventilation at thestreet level (Flickr: nicolasnova)38 This measure also helps to prevent excessive humidity and deterioration of buildingsdue to walls’ wetness, especially when the buildings and courtyards arerichly planted with vegetation.42Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

walks’ surfaces) – because vegetation, unlike albedo, truly affectsthe global radiation balance, and additionally has positive effects onthe restoration of water cycle and trapps pollutants.Apply these detailed design solutions for implementation of high albedowhere sealed surfaces are not avoidable 39 :a.Solar radiation• Substitute Portland cement concrete (with an albedo of about0.5) for asphalt concrete (albedo of 0.04-0.12). Use ultra thinwhite-topping.• Use light coloured aggregate in asphalt, tinted asphalt or whitebinder.b. Solar radiation• Use high-albedo asphalt coating that allows for an albedo ofover 0.5. (The average summertime surface temperature of highalbedocoated asphalt is about 48°C, compared to 68°C for conventionalasphalt.)• Use chip-sealing on low volume roads, a thin layer of asphaltcovered with partially exposed light colored aggregate. Chip sealingincreases albedo to as high as 0.35.• Paint sections of pavement with light-coloured paint: Bikelanes, crossing areas, intersections etc.Shading• Green the space between buildings, either with tall trees or withfaçade vegetation to prevent radiation reflection from the constructionmaterials and absorption by other built surfaces (fig. 56 a+b).Fig. 56 Solar radiation is likely to be absorbedor reflected when the urban surfaces consistsof man-made construction materials (a), ifvegetated however, the solar energy is transformedinto latent heat and thus “shades” theurban surfaces from overheating.a.• Plan for a higher H/W ratio of the streets to reduce incomingsolar radiation and overheating of the streetscape in the daytime.(Note: High density must be balanced-out with other measures alleviatingthe anthropogenic heat release, such as building greeningmeasures, adiabatic cooling systems, reducing vehicle traffic andenergy-responsible behaviour.)• Shade open spaces by deciduous trees or pergolas vegetatedwith deciduous plants to provide shade in summer but allowsunshine in winter.• Plant solar-friendly trees that provide shade in summer but allowsunlight in winter.• Apply urban design details that have an influence on the physicalcomfort of people in the street space. Extreme heat events affectpeople on their daily commute in the streets and in open space, andtherefore a special attention should be given to the built design ofstreets. A few design solutions providing protection from the directsun are (fig. 57):a. Overhangs projecting away from the wall of the building alongand over the sidewalk;c.b.Public groundPublic groundPrivate propertyPrivate propertyb. Setbacks of the ground floor, enlarging the width of sidewalkswith an arcade supporting the upper floors by columns (thisoption creates more space for landscaping and thus waterpermeable surface and it enhances the ventilation options in39 After NYC’s High Performance and Infrastructure Guidelines 2005, p. 82Public groundPrivate propertyFig. 57 Built design details for shading of thestreetscape3 Climate Sensitive Urban Design (CSUD) in moderate climate zone43

the street);c. Option b) + some of the upper floors projecting towardsthe streets 40 .Options a) and c) provide both shading and the overhang reduces downflowof wind along the windward walls along the street. In moderate climate,cases b) and c) proves as the most favourable, giving pedestriansthe choice to walk exposed to the sun or protected by shade.Fig. 58 Vegetated swale in an urban streetscapein Seattle. The higher the herbaceous orbushy vegetation the better. (US EPA)Water cycle and VegetationThe main objective is “resurfacing” – by making all surfaces“evapotranspirative landscapes”.VegetationThe imperative message is to increase the area of permeable soiland plantation, to increase the cooling through evapotranspirationand to provide cooling shade. This means bringing vegetated surfacesconnected to the soil back into cities (and beyond them) in anyform possible:Fig. 59 Vegetation covering all roofs of Bancode Santander, Madrid. (Irishtimes.com)• Create pockets of green space, vegetated swales in thestreets and scattered vegetation to help cool areas naturally(fig. 58).• Plant trees on vegetated surfaces, for like that, they achievehigher temperature reduction.• Plant vegetation on buildings in form of podium gardens, greenroofs (fig. 59) and façades (fig. 60): With the strong verticaldimension of cities, the potential planting area is not minimized, buton the contrary, enlarged – the surface areas that usually presenta burden to the climate, might thus be the opposite! Greening ofbuildings, especially green roofs and walls, is an imperative missiontowards alleviating the urban temperature extremes;• Conduct trams on green trails (fig. 61).• Create permeable and vegetated parking lots (fig. 62), preferablyplaced under vegetated pergolas or dense trees.Fig. 60 Vegetated façade in Malmö, Sweden.Rainwater managementThe general principle of the climate-related, decentralized urban hydrologicalmanagement translates into at least four design goals forurban districts, being of following priority 41 :1.2.Enhancement of vegetated surfaces for on-site evapotranspirationof rainwater through vegetation;Retention ponds and lakes for on-site evapotranspiration of rain-Fig. 61 Trams conducted on green trails,Freiburg-Vauban.40 Might be seen as compensation to the developer for the loss of the ground floorcommercial space, while providing additional shade. Particularly positive in residentialareas with small enterprises that do not require abundant space in theground floor level, and where the need for living space is higher.41 After SenStadt Berlin and TU Berlin 2010, p. 17; Emmanuel 2005, p. 125,amended.44Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

3.4.Rainwater catchment and re-use (particularly for irrigation);Infiltration into the ground (and, according to local hydrologicalconditions, possibly underground catchment and re-use) 42 .The design implications are:• Catch the rainwater from open space and green roofs and leadit into vegetated swales or overground catchment basins withconstructed wetlands (fig. 63), where it can evaporate effectively.• Design bioretention area to hold entire design storm, plus additionaldetention requirements, without overflow.• Disclose the water bodies. Bring the pre-existing, on-site,enclosed water channels above the ground level.Fig. 62 Vegetated parking lots, Dresden.• When designing (rain)water basins, always use wetland vegetationthat is in the moderate zone in terms of evapotranspiration themost effective type of vegetation. (Lower capacity catchmentbasins may be planned if accomodating more effective plants).• If retention is not possible on-site, collect and re-use the rainwater,especially for the irrigation of the vegetated areas and greenroofs/façades and as such return into the small water cycle as closeas possible to the site, where it has fallen on the ground.• Pave surfaces in a permeable way (fig. 64). Although vegetatedsurfaces are the most effective way to lower high urban temperaturesand to trap pollution contained in the rainwater, they cannotbe introduced everywhere. However, even when an area is to bepaved (such as roads or parking lots), in many cases it might consistof (semi)permeable surfaces – where the rainwater partially soaksinto the ground and partially evaporates; or be collected below thesurface level into cisterns and used for surface irrigation elsewhere.Fig. 63 Rainwater catchment basin and constructedwetland, Daimler Benz, PotsdamerPlatz, Berlin.Detailed design recommendations for the reduction of impervious areasin the streetscape are 43 :• Involve architecture on stilts to keep the sealed ground tominimum; which enhances the vegetated, evaporative area,and also the near-ground ventilation (fig. 65);• Use only pervious or semi-pervious pavements for openspace design and low volume roads (not applicable in case ofhigh volume roads).Fig. 64 Water permeable, loosely laid pavementenables vegetation growth where low intensityof use by pedestrians, Berlin-PrenzlauerBerg.• Edge pervious pavement areas with vegetated, evaporativestrips (particularly with vegetated swales) where the rainwater canbe led toward and infiltrate. Include trees and green façades, wherelarge-scale infiltration is not desired, to provide evaporation.• Reduce the street dimensions, such as lane widths, turningradius etc. to the minimum requirements.42 Priorities 3) and 4) should be weightened in any particular planning situation. InBerlin, for example, infiltration as in priority 4 is not as welcome because of highgroundwater levels.43 After NYC’s High Performance and Infrastructure Guidelines 2005, p. 80, 85,140.Fig. 65 Architecture (partially) on stilts enhancesthe infiltration area, Castello, Berlin-Lichtenberg.3 Climate Sensitive Urban Design (CSUD) in moderate climate zone45

• Reduce quantity of lanes, where appropriate. Introducetraffic calming areas (“Tempo 30” zones), which enablesmerging lanes and thus reduces the paved road width to lessthan if there were two lanes in opposite direction.• Implement traffic calming measures that involve perviouspavement.• Increase landscaping within sidewalk areas.• Use alternative soil stabilization resins to provide walkingor vehicle surfaces in light-traffic areas such as park walks andbike paths.• Share parking between businesses with different peak parkingdemand schedules.• Use the smallest allowable dimensions for regular parkingstalls; reduce row parking area that requires the most parkingspace.• Base parking lot design on average parking needs rather thanpeak parking needs.EvaporationWaste waterCondensed vapour retentionCaptured clean waterused for irrigation ofopen spaces andgreen roofs/evaporative coolingFig. 66 Wastewater use for UHI-mitigatingmeans. Wastewater collection, cleaning evapotranspiration,capturing of the condensedvapour and re-use.• For streets with a gradient in excess of 5%, use check dams toslow the flow of stormwater and allow for greater infiltration anduptake of water by plants.Manage the wastewaterWastewater may serve as a useful by-product of the urban system.Wastewater may be collected and evaporated within a closed facility –and the clean, condensed vapour used preferably in a way that helpstackle the UHI – such as irrigation of the open space or evaporativecooling. As such, the water cycle will be closed while using the watereffectively three or four times (harvesting of wastewater → water vapourre-use (e.g. toilet flushing) → irrigation) (fig. 66).Special design details of buildings affectingoutdoor conditionsReduce the side effect of abundant heat rejection by conventionalair conditioning in buildings into the adjacent environment by:• using adiabatic cooling systems combined with façade androof greenery (See Case study Institute of Physics in Berlin-Adlershofin Appendix 5).• introducing the water cooling effect in form of cooling towersas part of built structures (with the effect of direct evaporative aircooling) or ponds on rooftops with water as a cooling medium(indirect evaporative roof cooling) (Givoni 1998, p. 196-205).• placing the condensers of conventional air conditioningsystems at roof level (when implementation of these systems forsome reasons unavoidable). This rejects the heat high above thestreets, with minimum impact on the ground-level air temperatures(Givoni 1998, p. 283), however still increasing the adjacent urbanair temperature.46Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

General recommendationsSome of the possible solutions reach beyond the level of local interventionby urban designers (and beyond their authority), such as pursuingbehavioural change that would lead to overall lower consumption ofenergy – which, when exhausted as a by-product, has an effect on urbantemperature increase. For this, political decisions based on nationallyand internationally supported strategies (e.g. higher energy prizes,fuel taxes, and education) are necessary.Other strategies, however, can be followed by both municipal strategiesas well as by urban design, particularly the notion of the landuptake reduction 44 that can be achieved by:• cumulating land uses by combining parking, mixed use in thebottom levels and roof gardens with residential use in the upperlevels (See Appendix 6 Castello in Berlin) or by placing housing/commercial developments over road infrastructure (fig. 67).• vertical architecture: avoid buildings lower than four storeys.• optimizing the buildings’ volume by optimizing the usedspace. Reduce the room space in all building types – homes,offices, factories – to the necessary extent via small room areaand low ceilings. An example: the same building’s envelope withthe eaves height of 22 m 45 , can consist of 5 storeys á 4.4 m high,6 storeys á 3.6 m or even 7 storeys, each 3.1 m high 46 – andthus, in the latter case can accommodate almost 30 % more indooruse space than the former one (having the same negative climaticimpacts) (fig. 68)!• well-thought-of mix of uses that enables people walking andcycling within a short radius, as well as an effective public transportationsystem imply reduced space for roads and parkinginfrastructure.• education of public with attractive elements in public space suchas greened tops of busstops or other elements.This section showed the complexity and diversity of measures to tacklethe UHI. It might seem difficult to implement all of these means inevery urban project, particularly given the fact that the scale of thedevelopments and its location within the existing urban fabric variesfrom project to project. Nevertheless, the possibilities of a thoroughapplication should be investigated to achieve the most effective UHImitigation. A set of measures appointed in this CSUD Guidelines’ sectionwill be also applied later in this Thesis as a set of Climate-SensitiveUrban Design principles in the case study for Berlin’s Heidestrasse/Europacity(3.4). The built case study projects that are briefly presentedin the following section 3.3 (and in detail in the Appendixes 5-7) alsoaimed, more or less succesfully, at a thorough implementation of theappointed means.22 mFig. 67 Schlangenberger Strasse in Berlin isan example of cumulated land uses: An experimentalproject of a housing estate built abovea highway (Google)44 Because the original landscape cover has all bioclimatically positive functions.45 22 m is the common eaves height in Berlin’s Innercity.46 0.4 m ceiling thickness added to the rooms’ height of 4 m, 3.2 and 2.7 mFig. 68 Optimization of building’s volumes byoptimization of used space.3 Climate Sensitive Urban Design (CSUD) in moderate climate zone47

3.3 Examples of CSUD in built urban designprojectsFig. 69 Rainwater catchment basinThis section introduces briefly a few built projects, in which the climatesensitiveurban design (CSUD) principles have been succesfully applied:for instance, the building and the landscaping area of the Institute ofPhysics in Berlin, Adlershof; the mixed-used development Castello inBerlin; or the Malmö’s Western Harbour development in Sweden. Afew CSUD features that directly influence the Heidestrasse/Europacity’sdesign concept in the section 3.4 are described below; a detailed documentationof these projects is brought in the Appendices 5-7.Institute of Physics Berlin-AdlershofThe determining features of climate-sensitive urban design applied onthe building of the Institute of Physics are the decentralised rainwatermanagement (fig. 69), green roofs and façades (fig. 70), andthe openings in the building block for ventilation (fig. 70).Castello mixed-use development, Berlin, GermanyThe Castello development is not only extraordinary due to the very efficientland use that accommodates many uses on a small area andthus works against sprawl. It additionally features a large roof gardenarea, where all the rainwater from roofs and open space is beingcollected via overground streams (fig. 71) into a catchment basin(fig. 72) where it evapotranspires effectively. Another interestingarchitectural feature is the positioning of few buildings on stilts (fig.73), which improves local air circulation conditions and enlarges theevaporative ground surface. Finally yet importantly, the openings inthe apartment building block (fig. 72) serve for natural ventilation.Fig. 70 Green façades and openings in thebuilding block for ventilationFig. 71 Overground rainwater streamFig. 72 Rainwater catchment in a basin/ Opening of the building block forventilation.Fig. 73 Buildings on stilts for betterventilation and enhancement of theevapotranspirative surface area.48Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Bo01, Western Harbour Malmö, Sweden 47One very inspirative design feature of the Bo01 project is the advancedrainwater collection system that does not only collect all rainwaterfrom the area via overground water channels (fig. 74) into openedwater bodies (fig. 75), but it also creates an ecological, recreational andvisual resource. All the rainwater system elements are situated in thepublic open spaces among the housing blocks; and as such, they educatethe inhabitants and visitors about the great visual effect and the necessityto involve decentralized rainwater management in open space.Heinrich-Böll Settlement, BerlinThe Heinrich-Böll Settlement is an inovative development in Berlin-Pankow that connects a variety of eco-principles, such as solar orientationand building materials and a thorough rainwater managementconcept. It features convenient urban form of a medium-density developmentthat consists of loose blocks, providing sufficient naturalventilation (fig. 76), where some of the five-storey apartment buildingsare aligned into East-West oriented rows. The open space consistsexclusively of permeable and vegetated surfaces (fig. 77), rainwaterfrom roofs is being collected in overground water channels andled into a water basin in the south of the development.Fig. 74 Overground rainwater collectionKirchsteigfeld, PotsdamAmong many design principles applied in Kirchsteigfeld, one particularlyinspires the CSUD proposal for Heidestraße: the concept of carparking situated in the courtyards, on permeable pavement undervegetated pergolas (fig. 78).Fig. 75 Rainwater catchment basin47 Urban Design Compendium – Bo01, online; Gehl 2007, p. 80Fig. 77 Courtyards consist only of permeableand vegetated surfacesFig. 76 Loose urban blocks of the Heinrich-Böll Settlement (Google)Fig. 78 Parking lots on permeable pavementsunder vegetated pergolas3 Climate Sensitive Urban Design (CSUD) in moderate climate zone49

3.4 Climate-Sensitive Urban Design (CSUD) –Case Study Heidestrasse/EuropacityOne of the main tasks of this Thesis has been to compose a set ofCSUD guidelines. The task of this section is to apply these guidelinesto a Case Study project. For this purpose, an already existing urbandesign proposal for Berlin’s Heidestrasse/Europacity is reviewed for thepresence of the CSUD elements and principles. In case these elementsprove to be insufficient or missing, the composed set of CSUD guidelineswill be applied onto the existing masterplanning proposal. Finally,it will be summarized how the implementation of CSUD features affectsthe already existing masterplanning.Fig. 79/P1 Urban design proposal by ASTOC/Urban Catalyst/ARGUS, May 2010Review of the original Urban Design Concept for Heidestrasse/EuropacityThe documents used for investigation are the competition winning urbandesign plan developed by ASTOC/Urban Catalyst/ARGUS (fig. 79),the local development plans and other published documents availableon SenStadt – Heidestrasse, online. Questioned is, if the mitigation ofthe UHI effect at the district level has been considered and measuresfor its prevention accomodated in the existing urban design proposal;particularly the built volumes’ massing and urban geometry. AccordingFig. 80/P2 (below) Climate-related review ofthe urban design concept“Public openspace”, consistingof vast, imperviouslypaved surfaces,is a threat inoverheating/ Streetdirection in theSouth does notconform to theprevailing windsNon-permeable,large-volumeurban blocksdisable ventilationClosed urban edgehinders windpenetration from theexisting railwayventilation channel aswell as of the fresh airfrom the adjacent greenareasExceeding heating of thecommercial area to beexpected in summermonths due to the closedurban block structure thathinders local air circulationand ventilationClimatically positivesolution of loosetower buildingsallowing airpenetration into thedevelopmentPositive decreaseof building heighttowards the WestsupportsventilationSame-heightbuildingswithin theurban blocksdon’t supportturbulentventilationPartial openingsof the buildingblocks positivelyaffect local aircirculationWater channelenclosed in 3 mhigh walls hindersventilation andair humidity enterthe settlementVast area of pavedplaza andnon-vegetatedbuilding surface ,may significantlycontribute to theUHIClosed urban edge ofrelatively high buildings(six storeys) hindersventilation from theexisting water channelinwards thedevelopmentElevated groundfloors in the housingarea positivelycontribute to streetventilation and tostreet shading duringhot summersHard wateredge withoutvegetation50Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

to Mr. Werner Schlömer (SenStadt Berlin), the superior climatic aspects– in this case preservation of ventilation channels – had been consideredbefore the urban design competition took place and thus had to beinvolved in the design for the area; however not aspects such as urbangeometry 48 . Many other elements have not been addressed at this planninglevel either, such as buildings‘ and open space surface design.The documents’ review showed that the local development planningfor the Heidestrasse area is at the initial stage; and that the climatic aspectsof buildings and open space will not be on agenda until the “SustainabilityWorkshop Buildings” (“Nachhaltigkeitswerkstatt Gebäude”)in 2011. In this workshop, all climate-related aspects of buildings andof open space such as urban heat island, heat periods, vegetation,water bodies and water management are going to be discussed andpossible design adjustments are expected.The review of the existing urban design proposal brought followingconclusions (fig. 80, 81, P2, P3, P4 and the following page; figures“P” refer to the images in the posters):48 Urban geometry is usually not being on agenda in Berlin, as mentioned in thesection 3.1.Fig. 81/P3 (below and right) Proposed mainareas of interventionClimate Sensitive Urban DesignReview of the Urban Design Conceptfor Heidestraße/EuropacityLegendWind permeability of thedevelopment’s egde disabled orhindered by physical built elementsAreas likely to be a significant threat toclimate due to the urban form andgeometry and the lack ofevapotranspirative surfaces.Extreme heat loads caused by thedevelopment must be mitigated byadjustments of urban form andgeometry as well as introduction ofevapotranspirative surfaces.Areas with a high potential being asignificant threat to climate.Especially evapotranspirative surfaceconsiderations are necessary to avoidextreme heat load caused by thedevelopment.Areas with soft amendmentrequirements; do not require urbandesign conceptual changes.evaporative surface considerations arenecessary to avoid the abundant heatload caused by the development.3 Climate Sensitive Urban Design (CSUD) in moderate climate zone51

a.The proposal features a number of climatically positive urban designattributes:Fig. 82 Desired orientation of streets andbuildings, applying findings of a study by Herrmanand Matzarakis (2010). This study howeverdid not consider the direction of localwinds, being South-West in the Heidestrasse/Europacity Area.b.c.• The general urban form conforms to the desired values fordensity (the average urban density is FAR 3.3) and street geometry(streets have a H/W ratio 1 and higher);• The streets are oriented in a thermally convenient direction, inan oblique angle (30°) to the East-West orientation; and in aparallel to oblique direction of the prevailing Southwest-Westwinds, which provide good ventilation, importing the cooling airfrom the Fritz-Schloss-Park in the West. Although the East-Weststreet orientation, particularly in form of row buildings (fig. 82),would have been the most convenient, responding to the westernwinds prevailing in Berlin in the summer 49 , and reflecting therecommendation by Herrmann and Matzarakis (2010) 50 ; in thisparticular case however, the cold air streaming from the South-West (Environmental Atlas Berlin) must be taken into accountand as such has been considered in the proposal;• The loose high-rise buildings in the northern part of the devel-opment along the railway allow penetration (although someadjustments of their form are needed).The review of the proposal brought following conclusions aboutissues that yet had not been addresses properly:• Insufficient advantage taking of the existing ventilation chan-nels (railway and water channel) – building blocks are closedtowards these ventilation channels;• Building blocks are generally closed, particularly those in thewestern area, not permitting impinging ventilation or local aircirculation;• Same-height buildings within the urban blocks don’t supportturbulent ventilation;• Water channel is enclosed by ca. 3 m high walls, not allowingventilation from the water body enter the settlement;• Design for open spaces needs detailed design provisions toavoid over-heating due to vast, paved open space areas withinsufficient vegetation.The inclusion of the following elements had not been considered atthis planning level:• Evaporative surfaces, vegetated swalles and the like;• Decentralized rainwater management using overground rain-water system;• Building vegetating means (roof and façade greening);• Albedo of the development and other material characteristics.49 Environmental Atlas Berlin, online50 According to a study by Herrmann and Matzarakis (2010), in cool moderateclimates, the East-West orientation is the most appropriate one to lower downthe temperatures. In this study on geometry and orientation of idealized urbancanyon however, no local wind direction has been considered.52Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Suggestions for adjustment and complementation of the existingurban design proposalThe CSUD recommendations for Heidestrasse/Europacity reflect thefindings in the Thesis and the strategies used in the design of the builtprojects (section 3.3, appendices 5-7). The purpose is to point out allpossible urban design means for the UHI mitigation at the local level,making detailed design suggestions reaching beyond the level of generalmasterplanning.Following suggestions amend and complement the existing urban designproposal (figures “P” refer to the images in the posters):Action category ‘Urban form – density/compactness and geometry’To provide the most suitable built form conditions for sensible heatload reduction and ventilation, follow the design suggestions below.Remember that the particular use of buildings is not important, onlythe volumes, geometry and orientation of urban blocks and buildings.• Keep the average urban density below FAR 3.5 and the populationdensity below 250 dwellers/ha.• Pursue the streets’ height to width (H/W) ratio of about 1and higher, in an orientation parallel to slightly oblique to theEast-West direction to provide balanced shading/sun conditionsof the streetscape (fig. 83/P5).• As in the existing urban design concept, pursue six storey averagebuilding height 51 and corresponding street profile of 19 m width(the “European City” compact typology) that allows sufficientshading by buildings as well as ventilation.Fig. 83/P5 The urban geometry and density ofthe original proposal correlates with the CSUDrecommendations.• Adjust the design and orientation of the buildings in thesouthern part of the development to take the highest advantageof winds and to conform to the irradiation conditions (fig. P17).51 By designing low ceilings, a six-storey building will thus be about 20 m high. Inthe proposed CSUD concept however, the heights of the buildings is not the samebut varies; as previously mentioned, an “average height” allows, and in mostcases even demands, alteration within the development (See 3.2).3 Climate Sensitive Urban Design (CSUD) in moderate climate zone53

Action category ‘Ventilation’Ventilation is a decisive factor in air exchange and thus in balancingurban temperatures by transporting cool air into the heaten-up partsof settlements. To provide sufficient ventilation of the Heidestrasse developmentand so work against the heat loads inside of it, follow thesedesign rules:Fig. 84/P20 Air-permeable building blocks• Take advantage of the existing railway and river ventilationchannels by creating permeable eastern and western edges ofthe development, by loose buildings (particularly in the westernpart) and by lower building heights that support the “sheltereffect” (at the Eastern edge of the development) (fig. P6, P18).• Create higher buildings’ line and situate scattered higherbuildings along the Heidestrasse to create local turbulent ventilationconditions, and to avoid dispersing of pollution loads insidethe development.• Allow efficient local air circulation by wind penetration via openingsin urban blocks for courtyard ventilation – as air-permeable buildings(fig. P19, 84/P20) or loose building blocks (fig. 85/P21).Fig. 85/P21 Loose urban blocks• Build architecture on stilts to improve the local air circulation(fig. 65, 73, P22-24)• Disclose the water channel to bring more efficient temperaturereduction and humidity increase from the river (of up to 300 m)(fig. P29-30, 86/P31)• Involve flat roofs (fig. P18, P26-27), as they provide better ventilationat the street level. Flat roofs can easily be vegetated andadditionally provided with photovoltaic devices.• Vary building heights (fig. P25a) and carefully situate a fewhighrise buildings to improve the air turbulence and thus ventilationof the near-ground street level (fig. P25b).• Set-back the high-rise towers (fig. 38a).Fig. 86/P31 View of the proposed water channel(towards the North). The concept is todesign new channel with gradually ascendingslope to enable an efficient penetration of thecooling air into the settlement.Action category ‘Solar radiation’The way the solar radiation that reaches the urban area is transformeddetermines the extent of the heat island and the impact of the heatwaves. To prevent the transformation into sensible (thermal) heat,pursue the following rules:• Involve evaporative cooling through vegetation and waterbodies by any means possible (see Poster 5);• Shade open spaces by trees or vegetated pergolas (fig. 87/P17)and by (preferably vegetated) buildings’ overhangs (fig. P10).Fig. 87 Trees shading over Lenauplatz in Cologne,Germany. (Heribert Rösgen)• Rise the albedo of the development by using high-reflective, lightcolouredbuilding and paving materials. This, however, must beunderstood only as a measure of secondary priority, complementingthe transformation of solar energy into latent heat by plants andwater at spots where greening and design involving water is notpossible, such as road surfaces.54Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Action category ‘Water and Vegetation’The primary aim is to decentralize the rainwatermanagement, particularly to provide100% rainwater retention and preferablyevapotranspiration by plants and from openwater bodies on-site. 315 mm of rainfall inthe area during the summer half-year 52 impliesthat about 126000 l could be potentiallyevapotranspired from the 40 ha Heidestrassearea – meaning a heat load reduction byabout 283 MJ (210 MJ if taken that about75% evapotranspires from natural environments),or 79 MWh (75% = 59.25 MWh) 53 .To achieve this, adopt the following designsuggestions:• Create water retention basins and streams as part of the openspace design, preferably vegetated to filter and evaporate. This is tobe applied in both public and private open space as well as as a partof rooftop gardens on buildings (fig. 88, Poster 5, Appendices 5-7).• Use roof- and façade greening (fig. 88/P34, Poster 5)• De-pave and vegetate existing paved areas (brings localtemperature lowering up to 3°C, SenStadt Berlin and BSM 2009,p. 21)• Create smaller, dispersed and greened public spaces• Build architecture on stilts to enhance the evaporative area (fig.65, 73, P22-24)evapotranspirationthrough the plantson façadesevapotranspiration throughvegetated and permeable surfacesevapotranspiration through the roof vegetationinfiltrationevapotranspiration from the openedrainwater collecting channelevapotranspiration throughthe plants in the courtyardFig. 88/P34 Overground rainwater catchmentand vegetation in courtyards and on buildings.• Involve system of vegetated swales along the streets (fig. 89/P36, 90/P40) (Note: not to be confused with swales for infiltration– this would contribute to the Berlin-specific problem with risingground water levels and significantly limit the desired evapotranspiration.)• Attempt to catch all redundant rainwater that infiltrates intothe ground in underground cisterns and re-use it on site, preferablyfor irrigation 54 (fig. P36).• Create traffic calming zones (“Tempo 30” Zones) with reduceddriving lane width to enhance vegetated areas (fig. 93/P48)Fig. 89/P36/P41 System ofrainwater catchment basinsand vegetated swales in thestreetscape and open space.“solar” trees52 Out of 540-555 mm average annual rainfall in the Heidestrasse area. Source:Umweltatlas Berlin – Niederschlag (Environmental Atlas Berlin – Precipitation)53 For comparison, annual energy consumption of a three-person German householdis about 3.9 MWh (Agenda 21, online); meaning that an equivalent of theannual energy consumption by more than 20 families could be withdrawn fromthe heaten-up surface in the Heidestrasse area in form of latent heat and thuscool the district down. (The greywater use for irrigation and thus increased potentialevapotranspiration rates has not been considered in the calculation.)54 Building’s and pavement material finishing must not contain pesticides againstalgae and the like, otherwise the rainwater will become a threat to the irrigatedplants (Experience from the built project Institute of Physics Berlin-Adlershof bythe project supervisor Marco Schmidt).rainwater runoffSemi-permeable pavement-˚Cinfiltrationoverflow drain (collecting rainwater for re-use)-˚Cnative vegetationbioretention area min. 2mrainwaterFig. 90/P40 Vegetated swales in the streetscapesevapotranspiration3:1 max.slope swale3 Climate Sensitive Urban Design (CSUD) in moderate climate zone55

Fig. 91/P18 West-East (W-E) Section of thearea (proposed CSUD concept)• Keep paved areas to minimum. Where paving unavoidable, usepervious pavement means (except Heidestrasse with high-loadtraffic 55 ) – in low volume roads (in areas western and eastern fromHeidestrasse, and service areas), parking areas (combination withvegetated swales), sidewalks and walking paths, bike lanes, firetruck access lanes, city facilities including maintenance facilities,etc.• Use alternative soil stabilization resins in the courtyards, inparks, back alleys (fig. 77).• Place parking lots on permeable and vegetated surfaces andunder vegetated pergolas or dense trees (fig. P46-47).• Involve flat green roofs combined with photovoltaic devices.Roof vegetation reduces air temperatures in the proximity of the PVsystem and thus enhances its performance.Action category ‘Other design- and/or generalrecommendations’The following suggestions either apply to more than one previouslymentioned category, or don’t fall into any of them, and as such presentcomplementing recommendations that nevertheless address the tacklingof the UHI problematic:• Optimize the buildings’ volume by optimizing the used space:Reduce the room space in all building types – homes, offices, factories– to the necessary extent via smaller room area and low ceilings.As such, a 6-storey building will be about 20 m high (fig. 68/P15).• Cumulate uses e.g. by bringing greened courtyards above themix-uses below (Appendix 6 – Castello) or by situating buildingconnections above the street level (fig. P28).• Educate via publicly visible and visually enriching elements inurban design that contain signboards providing information, suchas busstops with green roofs (fig. P16), space-dividing vegetatedwalls or system of overground rainwater collection streamsand basins (see Poster 5, Appendix 7 – Bo01 Malmö).• Divide open space through vegetated, air-permeable pergolas(e.g. corners of building blocks).55 The expected traffic density of Heidestrasse is approx. 50,000 vehicles/d (SenStadt2009, p. 21). At these traffic volumes, potential infiltration into the ground,reaching the groundwater, must be avoided (SenStadt 2001, p. 98).56Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

The effects of the implemented CSUD features on the existingmasterplanningThe climate-sensitive planning for the Heidestrasse/Europacity intendedto bring valuable suggestions aiming to tackle the problematic,ahead of the appointed “Sustainability Workshop Buildings” in 2011.“The master plan was not conceived as a rigid, restrictive set of rulesand regulations” (SenStadt 2009, p. 11) and welcomes detailed considerationstowards climate-sensitive design. Thus, the planning suggestedin this Thesis has been understood as an adjustment of theexisting urban design proposal and has brought a number of interestingconclusions:The urban form, with the exception of a few minor adjustments, remainsas in the original proposal, for it is as such conforming to the appointedclimate-sensitive design characteristics. The main Heidestrasseartery’s proportions as well as the original urban block structure remain.There has however been a change in the height dispersion ofthe buildings for improving turbulent ventilation conditions, althoughwithout significantly influencing the overall urban density. The urbanblocks furthermore gain openings for better local air circulation andwind penetration; and local additions in the number of storeys do notonly enhance the desired turbulent ventilation but also (as a positiveside-effect for the developer) balance out the loss of the floor space.The main input regarding the urban form is thus in strengthening oflocal circulation and general wind conditions. The other, not less significantcomplementation lies in the decentralized rainwater managementand in the accentuation of vegetating measures. The main mean is thesurface design in the open space as well as on the buildings.Fig. 92/P17 Proposed CSUD conceptFig. 93/P48 Proposed street and courtyardprofile of the residential areaPlan flat vegetated roofsthat have cooling effectthrough evapotranspirationand can be combined withphotovoltaic systemsUse façade vegetation onevery vertical built surface(except windows).Provide parkinglots with vegetatedpergolas and withpermeable pavingElevate privategardens abovethe parking lotaccess roadUsepermeablepavementmaterialsReduce ceiling’s height to2.6 m for more efficientuse of space (morestoreys fit onto smallerground space)Design pebble/soil stripes alongthe façades toenable buildings’greeningInvolve vegetatedswales for rainwaterevapotransirationand infiltration witha min. width of 2 m.Reduce the street widthto the minimum ofthe required width forautomobile traffic in theopposite direction (4 m).Use semipermeablesurfaces forroads, sidewalksand parking lots.Collect theinfiltratedrainwater forre-use with anoverflow drain3 Climate Sensitive Urban Design (CSUD) in moderate climate zone57

4 ConclusionsBased on the need to address the climate-related problems in – and caused by – citieswith the help of urban design, this Thesis aimed to review the literature that brings recommendationsand guidelines addressing extreme heat conditions in moderate climatecities; and to use the findings as a base for a set of Climate-Sensitive Urban DesignGuidelines.The Thesis summarized the climatic features of cities, being dry and hot and thus havingthe effect of “concrete deserts” (that are accepted even within many “sustainable”developments). Throughout the world, there are researchers and designers addressingthis issue. Among them, Givoni (1998) and Emmanuel (2005) are considered the mostauthorative sources for urban designers. The review however showed that while focusingon the urban form and geometry, these sources do not address in depth the environmentalaspects of urban climatic considerations – the issues of energy flows and watercycle; and additionally avoid suggesting particular recommendations for designing inmoderate climates. Other sources focus well on the environmental processes in cities,such as the climatic aspects of energy flows and water cycles (Sukopp and Wittig 1998;Kravčík et al. 2007; Marzluff 2008); these sources however omit particular design recommendations.This gap, fortunately, is filled by other valuable sources that address thenatural water cycle and energetic processes – particularly by guidelines implemented byvarious cities (Chicago 2003, NYC 2007, Berlin 2010).Referring to the reviewed sources, this Thesis aimed at a connection of the main streams– the “environmental” and “architectonical” – in understanding the climatic aspects ofthe built form of cities. The main legacy is: Learn from nature, where the streams ofwater and ventilation are unobstructed (fig. 94).Fig. 94 Diagram of energy flows, water andwind in an idealized urban environment58Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

This implies that there is an acute need to understand:• ‘Solar radiation’ – as a desired energy flow; the priority in summer months howeverbeing to prevent overradiation and out of it resulting overheating. This implies thatthe urban form shall be compact and the spaces shaded. However, since built structuresand anthropogenic heat release contribute significantly to the city’s atmospherewarming, the compactness must conform to the ability of the given urbanenvironment to tackle the heat loads by providing sufficient evaporative cooling andnatural ventilation.• ‘Water’ – as rainfall that is to be kept on ground in water bodies and plants andevapotranspired into the adjacent atmosphere, while having significant coolingeffect;• ‘Vegetation’ not only as a component in parks – more than that, all natural as wellas man-made surfaces should possibly be vegetated;• ‘Ventilation’ – the air permeability must be provided at each city’s, district’s, urbanblock’s and building’s level. Here, the orientation of the streets, the urban form –density/compactness and geometry play a distinctive role.“Re-greening cities withan aggressive policy: notleftovers but priority.”(Katzschner and Katzschner2008)Based on this knowledge, the Thesis produced a comprehensive set of Climate-SensitiveUrban Design Guidelines. Briefly summarized, “Climate-Sensitive Urban Design” meansthat shading of open space in summer months is provided with the help of vegetation,built elements and appropriate urban geometry; permeable, high albedosurfaces are used where soil sealing is unavoidable; water, particularly rainwater, isconsidered being valuable element and as such is widely used in open space to providedesired cooling effect; vegetation is planted wherever possible, in open spacesas well as on the roofs and façades of buildings; ventilation channels are providedto allow the flow of cooler air from the surrounding countryside into the city centre, orbetween climatic compensation areas and impact areas; and finally yet importantly, eachurban district and urban block features sufficient natural ventilation provisions.These features were then applied and visualized in the design for a Case Study urbanproject, the Berlin’s Heidestrasse/Europacity, showing that it is possible to achieve moderate-to high density urban areas that, with particular design provisions, can effectivelyinfluence and alleviate the UHI at the local, district level.Unlike in other sources, the focus of this Thesis was not on buildings’ energy efficiencyand on motorized traffic reduction, but on buildings’ masses, urban form, and the thermaland climatic effects of urban areas as such.As the Thesis shows, many factors have to be considered before deciding on the appropriate,climate-sensitive urban form and design. Yet, besides the general aspectsdiscussed in the Thesis, the specific type of measures will depend on the particular geographicallocation and local conditions, such as terrain inclination, precipitation, etc.“Prescribing urban form to mitigate and adapt to climate change simultaneously isextremely challenging, if not impossible. Although mitigating climate change is bestachieved by designing settlement patterns that do not contribute to more GHG releasesdue to the excessive use of energy (…), adapting to climate change involves a morecomplex set of issues (Pizarro 2009, p. 42)”. This Thesis responded to this challenge andattempted to present a complex set of best urban design practices that will help citiesadapt to extreme temperatures and to mitigate the climate change.The aim has been to address not only urban design professionals and planning communitiesbut also other stakeholders in urban development; and to present and highlightthe applicability for any country or city in the cool moderate climate zone.4 Conclusions59

Complementing recommendations regarding the CSUD policiesfor municipalitiesIt is an immense challenge to enforce implementation of the CSUDpractices and gain an acceptation by municipalities, planning communities,developers and other stakeholders involved in the city-buildingprocesses. Therefore, the tasks are to research, to widen the gainedknowledge via education of the public as well as professionals, and toenforce the implementation with the help of guidelines, policies andbylaws. Given the complexity of this subject, that is not possibly to becovered within this Thesis, only a few thoughts on these issues will bebrought:It would make sense to have evaluation criteria for climatic factors,such as threshold values for maximal heat island intensity of adevelopment; minimum amount of climate-efficient cold airflow intoa settlement; or minimum size of ventilation channels that guaranteea sufficient provision of the city with cold air (Hahn-Herse 1997, Section‘Climate’, p. 61). Additionally, all cities should develop and pursuedesign guidelines, as, for example the Chicago’s ‘Stormwater BestManagement Practices’. The most effective way to make sure, that thedevelopments will conform to the desired values however are legallybinding prescriptions.A number of cities have introduced comprehensive green infrastructure(especially green roof) policies, such as Stuttgart, Münster, Toronto,Chicago, New York, Tokyo and many others; which turned to bylaw ina few of them (e.g. Toronto’s Green Roof Bylaw 56 ). These policies donot particularly address urban design but are a valuable way to enableeasier implementation.To increase the acceptability of the required design practices, the investorsmight be attracted by monetary offsets for including theclimate-sensitive design features, such as in the case of the fee splittingin Berlin, when the costs are reduced if rainwater is not led intothe central sewerage (SenStadt – Rainwater II, online). Another wayto motivate investors is by pursuing high climate-effective ratingin rating systems, such as the Canadian LEED-ND 57 or the GermanDGNB’s 58 “Quarter-Related Environmental Standards”.Finally yet importantly: the land uptake for urbanization results in destroyingclimatic compensation areas. To tackle this problem, national-widepolices are to be considered and possibly adjusted. One ofthe aspects is the pro-head housing area that is in some countriesconsiderably higher than in others; and does not necessarily mean anenhancement in the quality of life in the cities. In Shanghai, China, thehousing area is only about 9m 2 /p.P. 59 , whereas in Germany 42m 2 /p.P.or in USA 68.1m 2 /p.P. (ifS 2006). A way would be to educate and motivatethe public and to pursue compact types of developments not onlyby the Site Ocupancy Index, but also by the pro-head housing area.56 www.toronto.ca/greenroofs/overview.htm57 Details in LEED-ND provisions on UHI see Appendix 858 German Association for Sustainable Building59 de.wikipedia.org/wiki/Shanghai. Accessed on 26.7.201060Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

4 Conclusions 61

GlossaryAdiabatic coolingAlbedoAmbient temperature“A process used in air conditioning systems to air-condition buildings using evaporativecooling. The process is applied indirectly: one air flow is humidified as the other air flowis cooled. Evaporative cooling is a renewable energy, because only air and water are usedfor cooling. The principle of this process is the same as that of sweating, in which waterevaporates through transpiration. The heat required for the evaporation is drawn fromthe environment, which cools human skin.” (SenStadt Berlin and TU Berlin 2010, p. 62)Also called surface reflectance. Expresses the ratio of reflected radiation out of totalradiation. For example, vegetation reflects about 5-30% of shortwave solar radiationand hence has an albedo of 0.05-0.3; a colour-painted wall reflects up to 35% (albedo0.35), while a white-painted wall reflects up to 90% of solar radiation and has an albedoof 0.9 (Kravčík et al. 2007, p. 25).“Dry bulb temperature of the medium (air, water or earth) surrounding people, objectsor environment (Yeang 2006, p. 441).”Biotope Area Factor (BAF)“Instrument for securing “green qualities” in Berlin‘s inner city. It can be stipulated inBerlin as a statutory ordinance in a landscape plan. It contributes to the standardisationand concretisation of environmental quality goals, specifies the proportion of the area ofa property to serve as a planted area and takes on other ecosystem functions.” (SenStadtBerlin and TU Berlin 2010, p. 63)Constructed wetlandConvectionMan-made “environment characterized by shallow or fluctuating levels and abundantaquatic and marsh plants (...)” (Yeang 2006, p. 462); that pretreats rain- and “wastewaterby filtration, settling, and bacterial decomposition in a natural-looking linedmarsh.” (University of Minnesota, Extension, online).“The process of heat transfer by flowing and mixing motions in fluids. It is primarilydependent on air temperature and outside air motion (Roche and Liggett 2000).”Decentralized rainwater managementRainwater collection, evapotranspiration, re-use and infiltration on-site, where therainwater run-off from the development is not being led into wastewater or rainwatersewers.EvapotranspirationFloor Area Ratio (FAR)Green roof“The combination of evaporation of standing and soil water, and transpiration – themovement of water from the soil through a plant until it is released into the atmospherefrom leaf surfaces.” (Science Dictionary, online)“The ratio of the floor area of building to the area of the lot on which the building islocated.” (City of Boulder, online)“Vegetation cover on roof surfaces. There are two types: extensive and intensive. Extensivegreen roofs (also referred to as ecoroofs or living roofs): thin soil layer with horizontallyspreading, low-growing vegetation cover over entire roof surface that addsminimal loads to structure; serves as ecological storm-water management control byeliminating or delaying runoff. Also effectively reduces temperatures of the roof surfaceby absorbing heat from the sun, which may reduce the urban heat island effect. Intensivegreen roofs (also referred to as traditional roof garden): thick soil layer or planterswith vegetation, such as trees and shrubs that requires intensive care and maintenance;add substantial loads to buildings structure (Yeang 2006, p. 448)”; but also being moreefficient in term of evapotranspiration and thus in temperature lowering effects, sinceintensive green roofs often require increased irrigation (Marco Schmidt, consultation).62Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Ground waterHeat WaveH/W ratio“Water beneath the earth’s surface that fills underground pockets (known as aquifers) andmoves between soil particles and rock, supplying wells and springs (Yeang 2006, p. 448).”“Although there is no adequate definition of a heat wave, warnings are issued whenthresholds of daytime high and nighttime low heat index (Hi) values are exceeded forat least two consecutive days. The heat index is a combination of ambient temperatureand humidity that approximates the environmental aspect of the thermal regime of ahuman body, with the thresholds representing a generalized estimate of the onset ofphysiological stress. Heat waves are a major cause of weather-related deaths. With thecurrent concern for global warming, it is reasonable to suppose that they may increasein frequency, severity, duration, or areal extent in the future.” (Robinson 2001)The ratio of height (H) of the buildings to the spacing (width – W) between them. Thevalue of this ratio interprets, how much of incident solar radiation reaches the ground,and heats up the air near the ground (Givoni 1998, p. 247).Impermeable “Restricts the movement of products through the surface” (Yeang 2006, p. 450)Impervious surface area “Area that has been sealed and does not allow water to infiltrate, such as roofs, plazas,streets and other hard surfaces.” (Yeang 2006, p. 450)InfiltrationInsolationLatent heat“The passing of water into the soil or into a drainage system.” (Science Dictionary,online) v“A contraction of ‘incoming solar radiation’, meaning the amount of solar energy on agiven area over a certain period of time. The total amount of solar radiation (direct,diffuese and reflected) striking a surface exposed to the sky. (...)” (Yeang 2006, p. 451)“The heat taken in or given out when a solid changes into a liquid or vapour, or when a liquidchanges into a vapour at a constant temperature and pressure.” (Science Dictionary, online)“Latent heat is the only form of the Earth’s surface reaching transformed solar radiation thatis not connected with increasing the temperatures” (Kravčík et al. 2007, p. 25).Local development plan, binding land-use plan“The binding land-use plan lays down legally binding rules for the development andorganisation of sections of the municipal territory. It is developed on the basis of thepreparatory land-use plan, but, unlike the latter, it creates direct rights and duties withregard to the utilisation of the sites within its purview. (…)” (BSR Glossaries, online)Long-wave radiation“Terrestrial radiation in the spectral range 4000 – 100 000 nm. It is irradiated by theatmosphere and the earth’s surface.” (ThiesClima, online)Mean Radiant Temperature (Tmrt)Is “a very important factor in the human energy balance, and can be calculated fromtwelve radiation sensors and correlates very well with perceived human comfort” (Matzarakiset al., 2007)“Where Qa is the total shortwave and thermal radiation absorbed by the human body (Wm -2 ), ε is the thermal emissivity (-) and σ is the Stefan Boltzmann constant (W m -2 K -4 ).Directional dependant weighing factors and shortwave radiation absorption coefficientsneed to be considered for calculating radiation load on a human.” (Heusinkveld et al.2010, p. 435)Glossary63

Mitigation “Measures taken to reduce adverse impacts on the environment” (Yeang 2006, p. 452)Physiological Equivalent Temperature (PET)“An index used to describe the thermal situation of a person including the meteorologicalparameters Mean Radiant Temperature (Tmrt), Air Temperature (Ta), Wind Speed (v)and Vapor Pressure (RH). It ‘is defined as the air temperature at which, in a typicalindoor setting (without wind and solar radiation), the heat budget of the human body isbalanced with the same core and skin temperature as under the complex outdoor conditionsto be assessed.’” (Höppe 1999 in Katzschner 2010, p. 444-445)Orientation“The orientation of a surface is in degrees of variation away from solar south, towardseither the east or west.” (Yeang 2006, p. 453)Permeable “Having pores or openings that permit liquids or gases to pass through.” (Yeang 2006,p. 455)PollutantsPollutionPhotovoltaic (PV)RadiationRelative humidity“Any solid, liquid or gaseous matter that is in excess of natural levels of establishedstandards.” (Yeang 2006, p. 455)“Harmful substances deposit in the environment by the discharge of waste, leading to thecontamination of soil, water or the atmosphere.” (Yeang 2006, p. 455)“Capable of generating a voltage as a result of exposure to visible or other radiation.Solid-state cells (typically made from silicon) directly convert sun light to electricity.”(Yeang 2006, p. 454)“The process of heat transfer by means of electromagnetic waves. It is mainly dependenton surface temperatures of the body.” (Roche and Liggett 2000)“The ratio of the amount of water wapour in the atmosphere to the maximum amount ofwater vapour that could be held at a given temperature.” (Yeang 2006, p. 455)Retention basin “An area designed to retain run-off and prevent erosion and pollution” (Yeang 2006, p.458); and to serve for evaporation of the retained water into the adjacent atmosphere.Sensible heatSolar radiationIs “heat energy transferred between the surface and air when there is a difference intemperature between them”. (The Physical Environment, online: “Sensible Heat”.)“The energy-carrying electromagnetic radiation emitted by the sun. This radiationcomprises many frequencies, each relating to a particular class of radiation: high-frequency/short-wavelenghtultraviolet; medium-frequency/medium-wavelenght visiblelight; low-frequency/high-wavelenght infrared. This radiation is relatively unimpendeduntil it reaches the earth’s atmosphere. Here some of it will be reflected back out of theatmosphere, some will be absorbed. That which reaches the earth’s surface unimpededis referred to as ‘direct’ solar radiation, That which is scattered by the atmosphere isreferred to as ‘diffuse’ solar radiation. The combination of direct and diffuse is called‘global’.” (Yeang 2006, p. 459)Sustainable development(for the purpose of this Thesis) An (urban) development that does not contribute toenvironmental degradation and climate change; or does in a very low extent.Short-wave radiation“Solar radiation in the spectral range 290 – 4000 nm. The radiation source is the sun,the solar radiation is absorbed to some extend in the atmosphere, and partly on theearth’s surface.” (ThiesClima, online)64Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Sky view factor (SVF)A parameter that expresses urban geometry. “For an unobstructed horizontal area theSVF is eqaul to 1.0. For a point surrounded by close and very high buildings, or for a verynarrow street, it may be about 0.1” (Oke, 1981 in Givoni, 1998, p. 252).Site Occupancy Index (SOI)“The ratio of the actual surface area of a plot to permissible coverage. It is expressed asa simple ratio of built surface area to site area.” (BSR Glossaries, online)Solar-friendly treeSolar radiationSpecific heat capacityStorage heatUrban canyonA deciduous tree that “provides enough shade in summer thanks to the moderatelydense foliage; it however also allows sufficient sunlight permeate through the barebranches in the colder months, because it has an open or thin branch density, loses itsleaves early in fall, has no seed pods or catkins in winter and leafs out later in spring.Good examples include certain ash species, Chinese hackberry, European hackberry,Chinese pistache, and sawleaf zelkova”. (Perry, online)“The solar radiation is the radiation of the sun. The maximum power of the electromagneticradiation is the visible light, however, comprises also other electro-magneticwaves from X-rays and UV- radiation up to radio waves.” (ThiesClima, online)Represents “the amount of energy required to raise 1 kg of a substance by 1°C, andcan be thought of as the ability of a substance to absorb heat. Therefore the SI unitsof specific heat capacity are kJ/kg K (kJ/kg°C). Water has a very large specific heatcapacity (4.19 kJ/kg°C) compared with many fluids and is therefore considered a goodheat carrier.” (EngineerToolBox)Energy absorbed by various materials (construction materials, pavement, soil, etc.),known as ‘storage heat’, expressed by the specific heat capacity (Sass, online).“Is an artefact of an urban environment similar to a natural canyon. It is manifested bystreets cutting through dense blocks of structures, especially skyscrapers, which causesa canyon effect.” (wikipedia)Urban Heat Island (UHI)“Means the difference in the air temperature between an urban area and its surroundingenvironment. The main occurrence of this effect is at night, when the surrounding ruralenvironment cools down much faster than the city, where the heat stored in the buildingmass and roads is only slowly released into the atmosphere” (Urbis Limited 2007, p.15). The UHI augmenting factors are evapotranspiration loss, urban geometry, anthropogenicheat waste and urban “greenhouse” effect.Water cycleWastewaterThe term “refers to the movement of water, in all three of its physical forms, through thevarious environmental compartments.” (Yeang 2006, p. 449)The spent or used water from individual homes, a community, a farm or an industry thatcontains dissolved or suspeded matter.” (Yeang 2006, p. 461)Glossary65

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List of figuresCover frontLeftRight aboveRight belowSchematic diagram comparing the basic energy and water cycle characteristics of the natural environment(above) and an urban environment (middle). Image below suggests urban design implications according tothe findings in the literature review. (Graphic by Author)Wind-permeable building block in Berlin. (Flickr: Diogo CG. http://www.flickr.com/photos/11069904@N04/2129644980/sizes/o/. Accessed 7.9.2009)Castello, Berlin (Photograph by Author)Cover backDiagram of energy flows, water and wind in an idealized urban environment. (Graphic by Author)Figures in textFig. 1Fig. 2Fig. 3The cool moderate (temperate) climate zone ... . (http://www.diercke.de/bilder/omeda/800/12492E.jpg; www.diercke.de © Bildungshaus Schulbuchverlage Westermann, Braunschweig 2011, Accessed16.11.2010)Deforestation ... . (© GIZ / Lisa Feldmann, http://www.gtz.de/de/dateien/22748.htm, Accessed05.07.2011)... urbanization ... . (Photograph by Author)Fig. 4 “Natural” landscape ... . (Schmidt 2008)Fig. 5Urban “landscape” ... . (Photograph by Author)Fig. 6 Urban heat island profile. (Kravčík et al. 2007, p. 28)Fig. 7 Causes for UHI. (Emmanuel 2005, p. 25)Fig. 8 Values of solar radiation ... . (Kravčík et al. 2007, p. 24)Fig. 9 Global radiation balance in rural areas. (Schmidt 2010, p. 100)Fig. 10 Global radiation balance in urban areas. (Schmidt 2010, p. 101)Fig. 11Fig. 12Fig. 13Photographs of thin vegetation in the visible spectrum and in the infrared spectrum. ... . (Kravčík et al.2007, p. 27)A tree with 10 m diameter ... . (Graphic by Author)Albedo of various materials in urban environment. (http://www.ghcc.msfc.nasa.gov/urban/urban_heat_island.html.Accessed 24.8.09)Fig. 14 Photograph of the square and adjacent park in Třeboň, Czech Republic ... . (Kravčík et al. 2007, p. 33)Fig. 15 Aerial view of an industrial site in Berlin. (maps.google.com. Accessed 15.10.2010)Fig. 16Bioclimatic categorization of the same area as a “burden” area. (Environmental Atlas Berlin. Accessed15.10.2010)Fig. 17 The small and large water cycle. (Kravčík et al. 2007, p. 20)Fig. 18Extensive soil sealing in urbanized areas. (Photograph by Author)Fig. 19 The impact of the transformation of land ... . (Kravčík et al. 2007, p. 58)Fig. 20 Changes in hydrologic flows in urbanized catchments ... . (Göbel et al. 2004)Fig. 21 Global radiation balance on a green roof ... . (Schmidt 2010, p. 101)Fig. 22 The correlation of the UHI intensity and population size ... . (Matzarakis 2001, p. 55)Fig. 23 Canyon geometry and SVF. (Emmanuel 2005, p. 23)Fig. 24 Schematic distribution of the impinging solar radiation ... . (Givoni 1998, p. 248)List of figures71

Fig. 25 The ‘sky view factor’ ... . (http://www.knmi.nl/kd/weeramateurs/UHI/IMG/SVF.PNG. Accessed 2.6.2010)Fig. 26Fig. 27Fig. 28Fig. 29Fig. 30Fig. 31Fig. 32Fig. 33Fig. 34Fig. 35Fig. 36Albedo reflection and radiation absorption. (Graphic by Author)The larger the buildings’ surface in urban areas ... . (Graphic by Author)Streets parallel or in an small angle (of up to 10°) to the prevailing wind direction. (Graphic by Author)Streets oriented oblique to the prevailing wind direction. (Graphic by Author)Streets perpendicular to prevailing wind direction ... . (Graphic by Author)Air flow characteristic in urban areas. (Graphic by Author)Wedge-formed open space system ... . (Graphic by Author)Ventilation effect of a green space ... . (Graphic by Author)(Partially) opened block structure around the park Volkspark Friedrichshain ... . (maps.google.com. Accessed29.7.2010)High, enclosed houses’ front hinders ventilation ... . (http://i394.photobucket.com/albums/pp28/lynnevittorio/central-park-picture.jpg.Accessed 07.7.2011)Thoughtful planting of vegetation of certain height ... . (Graphic by Author)Fig. 37 Shelter effect. (Gandemer 1975 in CRU TUM, p. 244)Fig. 38Fig. 39Fig. 40Fig. 41Fig. 42Setback of the tower of a high-rise building or horizontal façade projections ... . (Graphic by Author)Basic principles of the thermal effect of a water body in an urban area. (Graphic by Author)High river embankments hinder cooling winds from the river channels enter the settlement. (Photographby Author)Perpendicular orientation of the buildings’ long axes to the water body ... . (Graphic by Author)Loose design of the building line on the border with an urban park or open space ... . Graphic by AuthorFig. 43 High temperatures in case of an urbanized area (above) ... . (Wong and Chen 2009)Fig. 44Schematic diagram comparing the basic energy and water cycle characteristics ... . (Graphic by Author)Fig. 45 The Chicago’s Guide to Stormwater Best Management Practices. (City of Chicago 2003)Fig. 46NYC’s High Performance Infrastructure Guidelines. (New York City Department of Design and Construction,and Design Trust for Public Space 2005)Fig. 47 Berlin’s Rainwater Management Concepts Guidelines. (SenStadt and TU Berlin 2010)Fig. 48Fig. 49Fig. 50Fig. 51Fig. 52Fig. 53Fig. 54Fig. 55Fig. 56Fig. 57Fig. 58High density settlements have a very high storage heat and anthropogenic heat load release. ... . (Sen-Stadt 2005, p. 6; © FTB Werbefotografie)City-wide ventilation channels. (Graphic by Author)Ventilation channels in urban areas as linear-oriented open spaces. (Graphic by Author)Design of the urban edge ... . (Graphic by Author)Extended access balconies ... . (http://www.provincia.bz.it/hochbau/images/0109_DSC_0170_rdax_800x450.jpg. Accessed 28.7.2010)Openings in compact urban blocks for better air circulation. (Graphic by Author)Architecture on stilts enables better ventilation near the ground and enhances the pervious area. (Graphicby Author)Flat roofs enhance ventilation at the street level. (Flickr: nicolasnova, http://www.flickr.com/photos/nnova/3557022388/sizes/o/; Accessed 7.9.2009)Solar radiation is likely to be absorbed or reflected ... . (Graphic by Author)Built design details for shading of the streetscape. (Graphic by Author)Vegetated swale in an urban streetscape in Seattle. (Image by the US Environmental Protection Agency,http://knol.google.com/k/-/-/17ruw3d8fyl4e/9auamn/bioswale-seattle.jpg. Accessed 4.12.2010)72Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Fig. 59Vegetation covering all roofs of Banco de Santander, Madrid. (http://www.irishtimes.com/newspaper/commercialproperty/2008/1001/1222724594809.html. Accessed 7.9.2009)Fig. 60 Intensively vegetated façade ... . (http://www.treehugger.com/branley-blanc.jpg. Accessed 7.9.2009)Fig. 61Fig. 62Fig. 63Fig. 64Fig. 65Fig. 66Trams conducted on green trails, Freiburg-Vauban. (Photograph by Author)Vegetated parking lots, Dresden. (Photograph by Author)Rainwater catchment basin and constructed wetland, Daimler Benz, Potsdamer Platz, Berlin. (Photographby Author)Water permeable, loosely laid pavement ... . (Photograph by Author)Architecture (partially) on stilts enhances the infiltration area ... . (Photograph by Author)Wastewater use for UHI-mitigating means. (Graphic by Author)Fig. 67 Schlangenberger Strasse in Berlin. (maps.google.com. Accessed 29.10.2010)Fig. 68Fig. 69Fig. 70Fig. 71Fig. 72Fig. 73Fig. 74Fig. 75Optimization of building’s volumes by optimization of used space. (Graphic by Author)Rainwater catchment basin. (Photograph by Author)Green façades and openings in the building block for ventilation. (Photograph by Rafael Pizarro)Overground rainwater stream. (Photograph by Author)Rainwater catchment in a basin / Opening of the building block for ventilation. (Photograph by Author)Buildings on stilts for better ventilation and enhancement of the evapotranspirative surface area. (Photographby Author)Overground rainwater collection. (Photograph by Author)Rainwater catchment basin. (Photograph by Author)Fig. 76 Loose urban blocks of the Heinrich-Böll Settlement. (maps.google.com. Accessed 29.11.2010)Fig. 77Fig. 78Fig. 79Fig. 80Fig. 81Fig. 82Fig. 83Fig. 84Fig. 85Fig. 86Fig. 87Fig. 88Fig. 89Fig. 90Fig. 91Fig. 92Courtyards consist only of permeable and vegetated surfaces. (Photograph by Author)Parking lots on permeable pavements under vegetated pergolas. (Photograph by Author)Urban design proposal by ASTOC/Urban Catalyst/ARGUS, May 2010. (http://www.stadtentwicklung.berlin.de/planen/stadtplanerische_konzepte/heidestrasse/de/downloads.shtml)Climate-related review of the urban design concept. Graphic by Author, on the base of a graphic producedby the design team of the original Heidestrasse proposal (SenStadt 2009)Proposed main areas of intervention. (Graphic by Author)Desired orientation of streets and buildings, applying findings of a study by Herrman and Matzarakis(2010). ... . (Graphic by Author)The urban geometry and density of the original proposal correlates with the CSUD recommendations.(Graphic by Author)Air-permeable building blocks. (Graphic by Author)Loose urban blocks. (Graphic by Author)View of the proposed water channel. (Graphic by Author)Trees shading over Lenauplatz in Cologne, Germany. (Photograph by Heribert Rösgen, http://www.ksta.de/html/artikel/1246439316844.shtml. Accessed 30.10.2010)Overground rainwater catchment and vegetation in courtyards and on buildings. (Graphic by Author)System of rainwater catchment basins and vegetated swales in the streetscape and open space. (Graphicby Author)Vegetated swales in the streetscapes. (Graphic by Author)West-East (W-E) Section of the area (proposed CSUD concept). (Graphic by Author)Proposed CSUD concept. (Graphic by Author)List of figures 73

Fig. 93Fig. 94Proposed street and courtyard profile of the residential area. (Graphic by Author)Diagram of energy flows, water and wind in an idealized urban environment. (Graphic by Author)Figures in PostersP1P2P3P4P5P6P7P8P9P10P11P12P13P14P15P16P17P18P19P20P21P22P23P24P25P26P27Urban design proposal by ASTOC/Urban Catalyst/ARGUS, May 2010. (http://www.stadtentwicklung.berlin.de/planen/stadtplanerische_konzepte/heidestrasse/de/downloads.shtml)Climate-related review of the urban design concept. (Graphic by Author, on the base of a graphic producedby the design team of the original Heidestrasse proposal (SenStadt 2009))Proposed main areas of intervention. (Graphic by Author, on the base of the Urban design proposal byASTOC/Urban Catalyst/ARGUS, May 2010. http://www.stadtentwicklung.berlin.de/planen/stadtplanerische_konzepte/heidestrasse/de/downloads.shtml)Proposed CSUD concept. (Graphic by Author, on the base of the Urban design proposal by ASTOC/UrbanCatalyst/ARGUS, May 2010. http://www.stadtentwicklung.berlin.de/planen/stadtplanerische_konzepte/heidestrasse/de/downloads.shtml)Urban form and geometry. (Graphic by Author)Ventilation concept. (Graphics by Author)Catch rainwater into water basins (VW Manufactory, Dresden). (Graphic by Author)Green all surfaces of buildings (Paul Lincke Ufer, Kreuzberg, Berlin). (Photograph by Marco Schmidt)Plant trees to provide shade (Lenauplatz in Cologne). (Photograph by Heribert Rösgen, http://www.ksta.de/html/artikel/1246439316844.shtml. Accessed 30.10.2010)Build design details such as façade overhangs to provide shade. (Graphic by Author)Involve vegetated swales in the streetscapes (Seattle). (Image by the US Environmental ProtectionAgency, http://knol.google.com/k/-/-/17ruw3d8fyl4e/9auamn/bioswale-seattle.jpg. Accessed 4.12.2010)Green both public and private parking lots (Jahnstraße, Dresden). (Photograph by Author)Use permeable pavement that allows growth of vegetation where not high pedestrian frequency (CourtyardMühlhauser Straße, Berlin). (Photograph by Author)Catch rainwater from the roofs into natural-like basins, as in the mixed-use development Castello in Berlin.(Photograph by Author)Build low ceilings that accommodate more use in more compact building envelope. (Graphic by Author)Vegetate busstops and other elements in public space to educate the public (Busstop in San Francisco).(National Geographic - Green Roofs. May 2009, p. 94)Proposed CSUD concept. (Graphic by Author)Section W-E. (Graphic by Author)Wind-permeable building block in Berlin. (Flickr: Diogo CG. http://www.flickr.com/photos/11069904@N04/2129644980/sizes/o/. Accessed 7.9.09)Axonometry A: Wind-permeable urban blocks and buildings in the commercial area. (Graphic by Author)Axonometry B: Loose urban blocks in the housing area. (Graphic by Author)Mixed use development “Castello”, Landsberger Allee, Berlin. (Photograph by Author)Mixed use development “Castello”, Landsberger Allee, Berlin. (Photograph by Author)Build architecture on stilts ... . (Graphic by Author)Vary building heights ... . (Graphic by Author)Build flat roofs ... . (Flickr: nicolasnova, http://www.flickr.com/photos/nnova/3557022388/sizes/o/. Accessed7.9.2009)Build flat roofs ... . (Photograph by Author)74Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

P28P29P30P31P32P33P34P35P36P37P38P39P40P41P42P43P44P45P46P47P48P49Connect buildings above the street level ... . (Graphic by Author)Current situation at the Berlin-Spandauer Schiffahrtskanal. (Photograph by Author)Water channel concept. (Graphic by Author)View of the proposed water channel (towards the North). (Graphic by Author)Overground rainwater catchment and evapotranspiration as one of the main design features in Bo01 WesternHarbour, Malmö, Sweden. (Photograph by Author)Overground rainwater catchment and evapotranspiration as one of the main design features in Bo01 WesternHarbour, Malmö, Sweden. (Photograph by Author)Overground rainwater collection. (Graphic by Author)Underground rainwater collection. (Graphic by Author)Involve overground rainwater catchment as part of every building block. (Graphic by Author)Constructed wetland Europaplatz: Catch rainwater, evapotranspirate and clean for re-use. (Graphic byAuthor)Rainwater basin and constructed wetland Daimler-Benz, Potsdamer Platz, Berlin. (Photograph by Author)Vegetated swales in the streetscapes. (Graphic by Author)System of vegetated swales in the streetscapes. (Graphic by Author)Façade greening concept for Heidestrasse. (Graphic by Author)A green façade of a residential house in Berlin, consisting of self-climbing vines. (Photograph by Author)The green façade of the Consorcio Building in Chile ... . (http://www.treehugger.com/consocio-building.jpg. Accessed 7.9.2009)Façade greening concept for other areas. (Graphic by Author)Park in courtyards (Kirchsteigfeld, Potsdam). (Photograph by Author)Park in courtyards (Kirchsteigfeld, Potsdam). (Photograph by Author)Design the residential area (East) as in the pictured street profile. (Graphic by Author)Vegetated green roof combined with photovoltaic devices. Ufa-fabrik, Berlin. (Marco Schmidt)Vegetated green roof combined with photovoltaic devices. School building in Unterensingen, Germany.(Earth Pledge Green Roofs Initiative (2005): “Green Roofs: Ecological Design and Construction.” SchifferBooks. P. 51)List of tablesTable 1Table 2Specific heat capacity of various materials. (EngineerToolBox, online)Runoff values for various urban environments. (Sukopp and Wittig 1998, p. 134; values from the germanDIN standard ‘DIN 1986’)75

Appendices76Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Appendix 1 Climatic effects of various urban land use categories(After Sukopp and Wittig 1998, p. 321-351, amended and completed)Type of landuseDirect impact and effects on climate,as well as the impact on water cycle,soils and vegetation (with consequencesfor climate)PrimaryclimaticfunctionMain CSUD action categories (for newdevelopments). 1Building areas with housing and/or commercial and mixed-use buildingsDensely builtupurban coresHighly influenced ventilation processes(regional winds don’t impinge in theiroriginal extent; however turbulences andstrong local winds possible on the streetlevel – depending on urban form, geometryand density); increased temperaturesdue to the concentration of human activitiesanthropogenic surface characteristicsof built areas; high levels of pollution(SO 2, dust). Almost total rate of soil sealing,very low vegetation to built structuresratio, very low evapotranspiration rate,almost all rainwater flows into sewerage.ImpactareaAim at mixed-use; keep the buildingdimensions down to the necessary extent;create small-scale open spaces for enhancinglocal ventilation conditions between thebuildings; create openings in buildings andbuilding blocks for the purpose of ventilation;green the roofs and façades to alleviatethe anthropogenic heat exhausts; usepermeable pavements, implement waterbasins, collect rainwater in water basinsan cisterns (on buildings if no space on thestreet level) and re-use it for green roofsand façade irrigation, for adiabatic cooling,for use in buildings.Closed urbanblock developmentsHighly influenced ventilation processes(mostly negatively, due to the closedblock structure), high temperatures, highlevels of pollution (SO 2, dust). Very highrate of soil sealing, low vegetation to builtstructures ratio, low evapotranspirationrate, high rate of rainwater flows intosewerage.ImpactareaCreate small-scale open spaces forenhancing local ventilation conditionsbetween the buildings; create openings inbuildings and building blocks for the purposeof ventilation; green the courtyardsand use permeable pavements; green theroofs and façades to alleviate the anthropogenicheat exhausts; collect rainwaterin water basins and cisterns (on buildingsif no space on the street level) and re-useit for green roofs and façade irrigation, foradiabatic cooling, for use in buildings.Exclusive residentialareas(villa quarters)If well greened-through, favourable microclimate,however lower population densityand thus likely to take over more landthan a denser urban form, with negativeconsequences for climate; to some extentretention of air pollutants, no significanttemperature increase due to greenery andsufficient ventilation. Variable rate of soilsealing; a balanced vegetation to builtstructures ratio and thus higher evaporationrate; considerable amount of rainwaterflows into sewerage unless collectedfor garden irrigation.Climateneutraleffect/ImpactareaGreen the courtyards and use permeablepaving; green the roofs and façades; implementwater bodies, collect rainwater inwater basins and re-use it for green roofsand façade irrigation, for adiabatic cooling,for use in buildings.Row houseresidentialareas withvast greenseparatorsThe greenery has mostly an undefinedopen space function, enabling windpenetration into the settlement – ventilationprovides microclimatically positiveenvironments; to some extent retention ofair pollutants.Climateneutraleffect/ImpactareaGreen the spaces between buildings and,where paving unavoidable, use permeablepaving; green the roofs and façades;implement water bodies; collect rainwaterand re-use it for green roofs and façadeirrigation, for adiabatic cooling, for use inbuildings.Appendices77

Type of landuseDirect impact and effects on climate,as well as the impact on water cycle,soils and vegetation (with consequencesfor climate)PrimaryclimaticfunctionMain CSUD action categories (for newdevelopments). 1Building areas with housing and/or commercial and mixed-use buildings (continued)Low-rise, detachedhousingareasFavourable microclimate, however havinglower population density and thus likely toconsume considerably more undevelopedland than a denser urban form, with obviousnegative consequences for climate.ImpactareaRise densities (preferably in the verticaldirection); green spaces between buildingsand, where paving unavoidable, usepermeable paving; green the roofs andfaçades; ; implement water bodies; collectrainwater and re-use it for green roofs andfaçade irrigation, for adiabatic cooling, foruse in buildings.Public buildingcomplexes(universities,research centres)Often situated in well-ventilated parklikecomplexes. Soil sealing rate dependson the exact purpose of the facility (e.g.research institutes may have more extensiveopen spaces for representativepurposes than universities, where a highfluctuation of students and thus higherrate of soil sealing might be needed);rainwater infiltration mostly on site, orinto rainwater basins that have environmentalas well as esthetical functions.ImpactareaAim at mixed-use; keep the buildingdimensions down to the necessary extent;green ospaces between buildings and,where paving unavoidable, use permeablepaving; green the roofs and façades;implement water bodies (on buildings ifno space on the street level) and collectrainwater and re-use it for green roofs andfaçade irrigation, for adiabatic cooling, foruse in buildings.Industrial areasAreas ofconcentratedcommerceand/or heavyindustryWaste artificial areas with very high ratioof non-permeable built surfaces (almost100% of all surfaces of buildings as wellas of spaces between them being sealed),usually well ventilated, however the heatemissions from buildings (emitted storageheat) and from anthropogenic activitiesconsiderably high.ImpactareaGreen of spaces between buildings anduse permeable paving when no danger ofthe pollution of soils; green the roofs andfaçades; collect rainwater and re-use it forgreen roofs and façade irrigation, for adiabaticcooling, for use in buildings.Traffic areas and road infrastructureMain roadsAlthough frequently accompanied byrobust vegetation, negative effects stillprevail: dispersion of air pollutants, 100%sealed surfaces, salts impinging into thesoils.ImpactareaRaise the albedo of the road surface, planthigh tree vegetation and involve vegetatedfilter strips for the catchment of pollutantsaccompanying the roads; for its coolingeffect, use the collected, filtered rainwaterfor road irrigation.Railway areasCool air transporting effects; extremeheating up on hot sunny days if darkmaterials (crushed stone or clinker) used;mostly accommodating random ruderalvegetation that in a little extent contributesto fresh air production.CompensationareaUse light coloured stone materials; connectwith adjacent built-up areas throughventilation lanes to take the highest advantageof the ventilation.1 The fields of actions vary for every category; although there are common built form arrangements than need to be considered for everyurban situation, as pointed out in section 2.2 “Basic energy, heat and water cycle characteristics”.78Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Type of landuseDirect impact and effects on climate,as well as the impact on water cycle,soils and vegetation (with consequencesfor climate)PrimaryclimaticfunctionMain CSUD action categories (for newdevelopments).Parks and open spacesParks andopen spaceswith highpresence ofgreeneryFavourable microclimate, retention of airpollutants. The higher presence of treesand larger vegetation, the more effectivealleviation of the temperature extremesand the higher pollutant trapping (andthus more effective fresh air production).Wind speed low due to the considerableroughness, therefore better for fresh airproduction than for air transport.CompensationareaSituate parks close to residential and commercialareas so that these can profit fromthe favourable climatic conditions; wherepaving unavoidable, use permeable pavingmaterials; incorporate water bodies.Grassy openspaces withlow vegetationNot as effective in fresh air production asforest-like areas, however excellent ventilationcapabilities (transport of fresh andcool air into built-up areas, while capturingof pollutants).Compensationarea/ventilationchannelIncorporate these greened ventilationchannels thoughtfully in emerging urbanareas.Plazas, urbanopen spacesVentilation function, but also high surfaceheating due to impervious paving.ImpactareaKeep the level of surface paving down tominimum; where paving unavoidable, useopermeable and light (high albedo) pavingmaterials, catch rainwater in water elementswith opened evaporative surface;shade through vegetation (trees, pergolas)to lower the solar radiation absorption andstorage.Sport complexesVentilation function, but also high surfaceheating due to impervious paving.ImpactareaKeep the levels of surface paving down tominimum; where paving unavoidable, usepermeable and light (high albedo) pavingmaterials, catch rainwater catchment elementswith opened evaporativee surface.Water bodiesRivers, standingwater,artificial basinsand designelementsAttenuation of temperature extremes,strong humidity producer, linear waterbodies are excellent for ventilation (coolair transport); smaller bodies moisten themicroclimate thanks to evaporation.Compensationarea/ventilationchannelEnlarge the water area to enlarge theevaporative water surface; avoid streamenclosure; avoid walls preventing ventilation(cooling winds) impinging intoadjacent urban areas, enlarge the riparian,vegetated areas at the water’s edge.ΔT (°C)Δr.F.65432100-10-203040Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14Difference in Temperatures ΔT (°C) and relative Air HumidityΔr.F. in different land use types, measured in Berlin atnight (Sukopp and Wittig 1998, p. 319):1. Urban core 2. Urban block typology 3. Suburbian highrisehousing and mixed use built construction 4. Rowhousing 5. Detached housing 6. Village 7. High-rise housingfrom the 60s and 70s 8. Industry and commerce with>85% impervious surface 9. Industry and commerce with50ha 13. allotment gardens 14. Woods and forestsAppendices79

Appendix 2 City of Toronto’s Study on Green Roof Benefits“Report on the Environmental Benefits and Costs of Green Roof Technology forthe City of Toronto” 1To determine the citywide benefits of green roofs, the study team calculated that approximately 5,000 hectares ofroof area is available for green roofs in the City of Toronto. The study findings, related to UHI effects, to climatechange, and to related costs, were divided into following cetegories:Stormwater runoff3• Reduction in stormwater flow of 12 million m per year (Capital expenditure reductions between 0.6 – 3.4%in stormwater treatment were estimated in case of capturing the rainfall through green roofs) / Infrastructuresavings worth between $2.8 and $79 millionEnergy consumption• Citywide savings from reduced energy for cooling is $21 million, equivalent to 4.15 KWh/m² per year• Cost avoided due to reduced demand at peak times is $68 millionUrban Heat Island effect• Widespread greening of Toronto’s roof would reduce local ambient temperature from 0.5 to 2°C• Citywide savings from reduced energy for cooling of $12 million, equivalent to 2.37 kWh/m² per year• Cost avoided due to reduced demand at peak times of $80 millionAir quality and emissions• Reduction in levels of CO, NO , O , PM , SO and in CO emissions2 3 10 2 2Building level benefits• Energy savings from better solar reflectivity, evapotranspiration and insulation• Green roofs last up to twice as long as regular roofsA detailed derivation of economic benefits from green roofs was made, in which many factors, individual costs andbenefits were taken into account, such as:• Urban heat island: Lowering temperatures by up to 0.8°C thus reducing energy demand in summerby up to 10%.• Energy costs savings: Saving on cooling costs estimated by approx. 15%, by green roof annual energy savings ata value between $2,500 and $12,500. These savings could significantly decrease the installation costs of greenroofs. It however needs to be noted that cooling cost savings due to green roofs in well insulated buildings witharound 2% is negligible (Emmanuel 2005, p. 41).• Discount rate applied to future costs and benefits; a range of 0-2% for climate change was used.• Air pollution and greenhouse gas effects: Significant reductions of airborne particulate matter and other airpollutants (valued at 10 – 30% reductions of particulate matter).• Food production on rooftops: Local food production has an impact on energy use related to the transportation offood and the availability of locally produced fresh food. (It is assumed that the value of food production is $1.07per m².)The Toronto example proves the wide-reaching benefits for the whole city, once the green infrastructure proposalshave been set into motion and implemented on a city-wide scale.1 Banting et al. 2005; Abstract80Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Appendix 3 BAF - Biotope Area Factor 2Similar to the urban planning parameters used in development planning, such as the gross floor area, the site occupancyindex, and the floor space index, which regulate the dimensions of use structures, the BAF expresses thearea portion of a plot of land that serves as a location for plants or assumes other functions for the ecosystem. TheBAF can be established with binding force in landscape plans for selected, similarly structured parts of the city.The BAF covers urban forms of use - residential, commercial, and infrastructural - and formulates ecological minimumstandards for structural changes and new development. All potential green areas, such as courtyards, roofs,walls, and fire walls, are included in the BAF.The BAF expresses the ratio of the ecologically effective surface area to the total land area.BAF = ecologically-effective surface areas / total land areaIn this calculation, the individual parts of a plot of land are weighted according to their “ecological value”.Types of surfaces and weighting factors: (Surface types not mentioned can be calculated as long as they have apositive effect on the ecosystem)Weighting factor /per m² of surface typeDescription of surfacetypesWeighting factor /per m² of surface typeDescription of surfacetypesSealedsurfaces0.0Surface is impermeableto air and water andhas no plant growth(e.g., concrete, asphalt,slabs with a solid subbase)Surface is permeableSurfaceswith vegetation,connectedto soilbelow1.0Vegetation connectedto soil below, availablefor developmentof flora and faunaPartiallysealedsurfaces0.3to water and air; as arule, no plant growth(e.g., clinker brick,mosaic paving, slabswith a sand or gravelsubbase)Surface is permeable toRainwaterinfiltrationper m² ofroof area0.2Rainwater infiltrationfor replenishment ofgroundwater;infiltration oversurfaces with existingvegetationSemi-opensurfaces0.5Surfaceswith vegetation,unconnectedtosoil below0.5water and air; infiltration;plant growth(e.g., gravel with grasscoverage, wood-blockpaving, honeycombbrick with grass)Surfaces with vegetationon cellar covers orunderground garageswith less than 80 cm ofsoil coveringVerticalgreeneryup to amaximumof 10 m inheight0.5Greeneryon rooftop0.7Greenery coveringwalls and outer wallswith no windows;the actual height, upto 10 m, is taken intoaccountExtensive and intensivecoverage ofrooftop with greenerySurfaceswith veg-Surfaces with veg-etation,etation that have nouncon-connection to soil belownected tobut with more than 80soil belowcm of soil covering0.72 Abstracts from www.stadtentwicklung.berlin.de/umwelt/landschaftsplanung/bff/index_en.shtml (Accessed 19.9.2010)Appendices81

(BAF - Biotope Area Factor continued)The BAF values vary for the various development and use structures. For example, BAF for new residential areas is0.6, for commercial areas 0.3, for public facilities 0.6 (0.3 for schools).Calculation exampleEach plot of land can be designed in various ways. In principle, measures that lead to an expansion of the area ofvegetation on the ground are given priority. Only then should additional possibilities, such as the replacement ofasphalt and concrete with other surfaces, be utilized.Land area 479 m²Developed area 279 m²Undeveloped area 200 m²Degree of development 0.59The courtyard is mainly covered with asphalt. There is gravel with grass coverageon the periphery, and the tree stands in a soil bed that measures 1 m².Calculation: BAF Ground state140 m² Asphalt x 0.0 = 0 m²59 m² gravel with grass coverage x 0.5 = 30 m²1 m² open soil x 1.0 = 1 m²BAF = 31/479 = 0.06BAF target = 0.3Calculation PlanningBuilding a covered bicycle stand means that the portion of partially sealedsurfaces must be increased.It is therefore necessary to utilize roof and fire wall surfaces in order to achievethe required BAF.Calculation: BAF Planning21 m² concrete surface x 0.0 = 0.0 m²79 m² area covered by vegetation x 1.0 = 79.0 m²100 m² mosaic paving x 0.3 = 30.0 m²10 m² greenery covering walls x 0.5 = 5.0 m²41 m² greeneryx 0.7 = 29.0 m²covering rooftopBAF = 143/479 = 0.3Legal guidelinesIn Berlin, the BAF can be established primarily in landscape plans as an environmental planning parameter. Theinherent legally binding arrangements can be found in Berlin’s “Handbuch der Berliner Landschaftspläne” 3 . However,the BAF can also be utilized in all developed areas as a guideline for environmental measures. Consequently, siterelatedstandards are to be implemented for building projects in developed areas in order to achieve the goals of theprotection of nature and of landscape maintenance.3 www.stadtentwicklung.berlin.de/umwelt/landschaftsplanung/handbuch/de/biotopflaechenfaktor/index.shtml#nummer1182Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Appendix 4 Tempelhof Study 4The study for the former Airport area Berlin-Tempelhof, conducted to investigate the climatic impacts of urban planningintentions, provides valuable conclusions applicable in the design of the climate-sensitive urban unit for theHeidestrasse area.First, the study brings a number of climate-related findings on the status-quo of the former airport (that are consideredin the design of the Heidestrasse/Europacity area)1.2.At the present, there is a considerablyclear distinction of climatic compensationand impact areas (The aim forthe Heidestrasse area is to balancethe negative climatic effects withinthe urban (impact) areas with thehelp of CSUD provisions);The built-up areas with loose builtform and well greened-through (inthe South-West) have slightly lowertemperatures than the denselybuilt-up areas with less vegetationand high buildings’ and surfacesealing ratio; yet are still classifiedas “heat island areas”, because thevegetation rate is not high enough tobalance the anthropogenic heat andstored heat in buildings. (The aim forthe Heidestrasse area is to lower theheat island extent within the looseurban structure by involving waterbodies, abundant vegetation as wellas ventilation provisions);Temperatures 2 m over ground (SenStadt Berlin and BSM 2009, p. 16)3. The ventilation from the open space areas does not permeate the built-up areas due to the closed building blockson the edge. (The aim for the Heidestrasse area is to provide sufficient ventilation penetrating from outside thedevelopment inwards.)4.Additionally, the estimated climatic effects of three various urban development scenarios were compared in thestudy. The estimations, made for the land use plan level 1:10,000, made valuable provisions on the plannedurban areas within the Tempelhof field, in particular on urban density and ventilation channels. Insights wereoffered into the temperature effects of urban density: The “W2” categorized planned housing areas (FAR up to1.5) feature due to the looser structure and higher distance between the housing blocks temperatures lower byup to 1°C, compared to the small industry areas of higher density and compactness (SenStadt Berlin and BSM2009, p. 16). Even higher efficiency (means, temperatures lower by 1°C and more) will be achieved in the builtform alternative with even looser structure and higher open space ratio (FAR up to 0.8) (SenStadt Berlin andBSM 2009, p. 18).The study did not consider potential building greening measures and thus additional enhancing of the vegetated(means, fresh air producing) area within the new built-up areas; and relied on the open space greening betweenbuildings and considered the usual building volumes characteristics. To assume is that if prevailing surface area ofthe buildings was vegetated, lower temperature differences compared to the Tempelhof Field’s open space would tobe expected. These lacking points are introduced in the Heidestrasse CSUD.4 SenStadt Berlin and BSM 2009Appendices83

The building of the Institute of Physics with newlyplanted facade vegetation (Photograph by Author)Appendix 5 Institute of Physics Berlin-Adlershof 1Project facts:LocationNewtonstraße 15, 12489 Berlin, AdlershofProject team: Architects Georg Augustin, Ute Frank,Berlin; Landscape Architects Stefan Tischerand Joerg Th. Coqui, BerlinBuilder/OwnerUserLand Berlin, represented by the Senate forUrban Development, Department V.Humboldt University BerlinView from above (Google)Construction 1999-2003Usable floor area 9,700 m 2Total ground surface area 19,000 m 2Received the Berlin Architectural Award in the year 2003Design features:• The Institute of Physics of the Humboldt University Berlin is anexceptional project of ecological urban development featuringvarious innovations of sustainable construction. The project consistsof one building that accomodates five greened and naturally wellventilatedcourtyards.Rainwater catchment basin in one of the courtyards(Photograph by Author)• The project includes, among other features, an ongoing monitoringof the water consumption of different plant species of the façadegreening system and of resultant evaporative cooling along with itseffects on the overall energy consumption of the building.CSUD principles:• Decentralised rainwater management. The building is notconnected to wastewater or rainwater sewers. Rainwater is storedin five cisterns in two courtyards of the building, and primarily usedfor the irrigation of the façade greening system and the adiabaticcooling. Storm water events with heavy rainfall are managed withan overflow to the pond in one of the courtyards, from which thewater can evaporate or drain into the ground through vegetatedsurface areas. Some of the roof surfaces are extensively greened.One of the green roofs (Photograph by Author)1 Senstadt: Institute of Physics in Berlin-Adlershof, online84Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

• Passive building air conditioning. Measurements taken at two roofs in Berlin-Tempelhof show that 58% of theradiation balance can be converted into evapotranspiration during summer months. In comparison, non-greenedroofs can convert 95 % of the radiation balance into heat. Façade greening can even more significantly impact on abuilding’s energy balance. The average evapotranspiration rate between July and August was between 5.4 and 11.3millimetres of water per day depending on the respective floor, i. e. an average cooling value of 157 kWh per day.• Green façades. Green façades provide an active solar shading system. As a “side effect”, they illustrate thechanging seasons. Ten types of climbing plants have been planted in 150 planters on nine different buildingfaçades. Façade greening is closely related to the effort of optimising energy efficiency of the building. Plantsprovide shade during summer, while in the winter the sun’s radiation is able to pass through the glass front. Thegreening also harnesses evapotranspiration to improve the microclimate inside and around the building.• Openings in the block for ventilation. The building is not designed as a compact block, but has openings intothe courtyards that allow air circulation and thus a better cooling effect.• Adiabatic cooling systems. During summer months, rainwater is used for air conditioners in the building. For theprocess of adiabatic cooling, rainwater is sprayed on the building’s exhaust air whereby fresh air entering the buildingis cooled through a heat exchanger. This process of air conditioning of a building is effective in cooling incoming airto a temperature of 21–22°C with outside temperatures of even up to 30°C, without having to revert to technicalcooling systems. Evaporation of water is an economic and effective means for the air conditioning of a building. Theevapotranspiration of one cubic meter of water produces an evaporative cooling with a value of 680 kWh. Adiabaticcooling systems can practically be seen as substitutes for conventional air conditioning technologies.The green façades on the southern façade and in one of thecourtyards (Photograph left by Rafael Pizarro; below by Author)Appendices 85

Castello development, seen from LandsbergerAllee (Photograph by Author)Appendix 6 Castello mixed-use development,Berlin-LichtenbergProject facts: 1LocationDeveloperArchitectCorner of Landsberger Allee and Judith-Auer-Road,Berlin LichtenbergUniversale International GmbHHinrich BallerConstruction begin June 1998Construction costs84 Mio. German MarkView from above (Google)Spacious roof garden enclosed by wind-permeablehousing block (Photograph by Author)The commercial centre below the roof garden(Photograph by Author)UsesShopping center with 5500 m 2 of commercialspace for shops, services, restaurantsand bistros; 1000 m 2 are for offices, doctors’offices and law firms; Underground garagespace that accomodates 150 parking lots;193 two-, three or four bedroom apartments;some of them sharing one of themany terraces. The entire building isconstructed from prefabricated parts, whichare manufactured in Hennigsdorf, all beingcustom products.Urban design features:• The mixed-use development is accommodated within one “building”:parking underground, retail and commercial space on the groundlevel and apartments as well as a vast roof garden containing rainwaterdesign elements, playgrounds and semiprivate open spacefacilities on the top of the commercial level. Apartments are situatedin a loose, air-permeable building block situated above thecommercial facilities. The compact development takes a highadvantage of space, while allowing the “building” carry features ofan urban block that alleviates the UHI effects on the local level.1 Tagesspiegel – Castello (online)86Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

CSUD elements:• Effective land use that accommodates many useson a small area and thus works against sprawl.• Roof garden covers the whole roof area inside ofthe block of buildings.• Rainwater is being collected via overground“streams” into a catchment basin enablesevapotranspiration.Rainwater is collected via attractive open-spaceelements... (Photograph by Author)• Buildings (partially) on stilts enlarge the evaporativeground surface as well as the open space.• Openings in the apartment building block servefor natural ventilation.• High-reflective buildings’ and roof surfaces.... and led in overground streams... (Photographby Author)Above: Buildings on stilts are highly effectivefor enlarging the evapotranspirativearea and for improving local aircirculation. (Photograph by Author)Below: The roof garden/courtyard ofthe castello development with windpermeablearrangement of the houses(Photograph by Author)... into a catchment basin on the east side ofthe development (Photograph by Author)Appendices87

Bo01 seen from the 56th floor of the TurningTorso. (Flickr: dhogborg)Appendix 7 Bo01, Malmö, Sweden 1Project facts:Waterfont promenade in Bo01m with the landmark“Turning Torso” in the background. (Photographby Author)LocationProject TeamConstruction beginUsesUrban design features:City of Malmö’s Western HarbourMKB Fastighets AB, Malmö, Sweden, LarsBirve, Ingvar Carlsson, Local government,National government, European Union, PPPDeveloper: SWECO Projektledning AB Architects:Moore Ruble Yudell Architects & Planners;FFNS Arkitekter ABIn 2001, Sweden’s International HousingExhibition provided the occasion to create anew urban settlement on reclaimed industrialland.Distinctive, resource efficient and liveableplace with 500 homes, retail, commercialand community facilities.• Bo01 represents part of Malmö’s transformation from a depressedindustrial city to a thrieving new multi-cultural centre of knowledgeand advancement, the main principles being “Responding to microclimate”and “Delivering quality and sustainability”.Decentralized rainwater management and avisually effective design of the overgroundrainwater elements (channels, catchment basins)are two of the main CSUD features of theBo01 development. (Photograph by Author)• Sense of human scale: Delineating views and providing a sense ofintrigue and delight through a sequence of spaces. Clear “fronts” and“backs” of housing blocks provide semi-private space for residents.1 Urban Design Compendium – Bo01 (online) and Gehl 2007, p. 8088Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

• The development is energy-neutral, producing as much renewableenergy as it consumes, due to both alternative energy sources andenergy efficient design. Orientation of building façades and roofforms maximise solar gain. In addition, solar thermal panels, windturbines and photovoltaics help minimise energy use while maintainingthe overall integrity of the architectural and urban form.Bo01 residents are encouraged to monitor their energy consumptionusing information technology installed in their homes.• Apartment buildings have been designed for mixed use – the groundfloor level of buildings has a higher floor to ceiling height to alloweasy conversion to shops when and if the need arises.CSUD principles:• The irregular street grid gains shelter from strong and coldsea winds, while allowing desirable East-West orientation ofthe housing blocks.• Five-storey blocks front the sea, protecting inner buildings whilereinforcing the character of the sea-front promenade.• Varied forms of on-plot vegetation such as green walls and roofsreduce surface water runoff within the development.• An advanced urban drainage system creates an ecological,recreational and visual resource. All buildings are provided with anadjacent rainwater retention area and channel around them; therainwater is led in overground open channels into opened waterbodies that are situated in the publicly accessible squares amongthe housing blocks – although the planners could have led therunoff easily into the sea.The aerial photograph shows the distortedgrid of the development that not only createsa variety and diversity of spaces, but alsoshelters from strong winds and complies withthe desired East-West orientation of buildings.(Google)• Openings of the building blocks improve the air circulationwithin the inner developed area.• Parking lots are paved with permeable materials.• Buildings partially on stilts enable multiplication of uses:housing/open space or office space/road infrastructure.Buildings on stilts enable multiplication of uses,in this case housing above public open space.(Photograph by Author)Shallow slopes enable easy access to water and air circulation between the coolwater body and the adjacent “warmer” urban area. (Photograph by Author)Simple design elements allow growth of vegetationon buildings. (Photograph by Author)Appendices89

(Bo01, Malmöcontinued)Water is the leading design element of the development, not only as a visual but also as functional resource.Visually impressive open space design always incorporates (rain)water, vegetation and (semi-)permeablesurfaces. Above: housing and private gardens along the water channel. Below: the rainwater basins are partof every of the open space, even of every tiny plaza between the housing blocks. (Photographs by Author)90Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

Appendix 8 The LEED-ND provision for UHI effect mitigationLeed-ND US, Canada has provisions for the Heat Island Reduction – where however with only 1 point out of 110possibly rewarded for heat island mitigating measures, the requirements for the UHI reduction are rather weak; andare not enforceable. Critique also is that the LEED-ND certification omits considering the hardscape area of façades,which due to its surface character contributes to the UHI, and avoids pursueing façade vegetating measures. See thedetails in LEED-ND provisions on UHI below. Stormwater Management has a slightly higher rating in the LEED-ND rating system, where in various certificate levels, 80 – 95% of rainwater is required to be retained, and can berewarded by 1-4 points.GiB Credit 9: heat island reduction (1 point)IntentTo reduce heat islands to minimize effects on the microclimate and human and wildlife habitat.RequirementsOption 1. Nonroof measuresUse any combination of the following strategies for 50% of the nonroof site hardscape (including roads, sidewalks,courtyards, parking lots, parking structures, and driveways):a.b.c.d.Provide shade from open structures, such as those supporting solar photovoltaic panels, canopied walkways, andvine pergolas, all with a solar reflectance index (SRI) of at least 29.Use paving materials with an SRI of at least 29.Install an open-grid pavement system that is at least 50% pervious.Provide shade from tree canopy (within ten years of landscape installation).orOption 2. High-reflectance and vegetated roofsUse roofing materials that have an SRI equal to or greater than the values in Table 1 for a minimum of 75% of theroof area of all new buildings within the project; or install a vegetated (“green”) roof for at least 50% of the roof areaof all new buildings within the project. Combinations of SRI-compliant and vegetated roofs can be used providedthey collectively cover 75% of the roof area of all new buildings (use the equation in Option 3).Table 1. Minimum solar reflectance index value, by roof slopeRoof slope SRILow (≤ 2:12) 78Steep (> 2:12) 29orOption 3. Mixed nonroof and roof measuresUse any of the strategies listed under Options 1 and 2 that in combination meet the following criterion:Area of Nonroof measures / 0.5 + Area of SRI roof / 75 + Area of vegetated roof / 0.5 ≥ total Site hardscape Area+ total roof AreaAppendices91

Appendix 9 Posters Climate-Sensitive Urban Design – Case StudyHeidestrasse/Europacity92Climate Sensitive Urban Design in Moderate Climate Zone: Responding to Future Heat Waves. Case Study Berlin Heidestrasse/Europacity

“Climate-Sensitive Urban Design aims at the combination of various elements that mitigate theurban heat island (UHI) effects. The design is to involve street profiles, building orientations andappropriate urban density and compactness, which provide adequate geometry for shading andnatural ventilation of streetscapes and buildings and thus alleviate the anthropogenic heat loads.The urban form arrangements are to be combined with the decentralized overground rainwatermanagement, water bodies, green roofs, podium gardens, balcony/terrace gardens, façadegreenery, street plantings (trees and vegetated swales), foregardens and any other possible meansof greening cities, and with the (re-)creation of natural-like, air- and water-permeable surfaces.”About the authorJana Milošovičová is a Master’s degree candidate in Urban Design. Her LandscapeArchitecture Diploma’s Thesis (2006) dealt with a green space system for the citycentre of Bratislava (Slovakia) where, among other issues, she addressed urbanclimate, water and vegetation. Since 2006, Jana’s focus has been on the thoroughinvestigation of the environmental aspects of urban design and planning, with aparticular interest in how can urban climate be influenced by urban design andhow design and planning can address global warming mitigation and adaptationin moderate climate cities. This Thesis document is Jana’s most recent andcomprehensive work on Climate-Sensitive Urban Design.