PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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and power demands of the building. These mainly include the modelling of thebuilding environment (e.g. building geometry, fabric, shading etc.), the electricaldemand, the internal heat gains and the domestic hot water profiles. The chapter alsoincludes an analysis of how the various operating conditions being investigated (e.g.type of building fabric, building size and occupancy, appliances’ energy-efficiencyetc.) were factored in the modelling process.Chapter 3 describes the micro-trigeneration plant developed using the buildingsimulation tool ESP-r. The chapter makes specific reference to the basis of plantcomponents and network design and the implementation of plant systems’ controlstrategies. This chapter also outlines the development of a new generic dynamicmodel for a single-effect lithium bromide-water absorption chiller used extensivelyin the modelling and simulations performed.Chapter 4 explains the type of scenarios investigated together with the assessmentmethodology and associated performance metrics used to assess the value of theproposed scenarios. Each particular scenario modelled was used to assess one of theindividual operating conditions being investigated. Based on the data obtained fromthe simulations performed, the effect of the different operating conditions on themodelled micro-trigeneration system could be assessed.Finally, Chapter 5 presents and discusses the results obtained for the differentscenarios investigated in this research. The first part of the chapter is a general oneand provides an analysis of how improving the building fabric and the electricalefficiency of appliances would affect the building’s energy demand. The second partof the chapter discusses the results obtained for the different micro-trigenerationsystem scenarios using three different assessment criteria: energetic, environmentaland economic.6.2 Outcomes of the thesisThe outcomes of this thesis can be grouped in two categories. The first categorydescribes outcomes obtained as a direct result of the modelling process. These240
primarily include:i. Improving the modelling of residential electrical loads by providing the means togenerate high resolution electrical demand profiles including the effect of futureenergy-efficiency improvement measures. A method was developed wherebylow-resolution electrical demand datasets can be used to create high-resolutiondemand data reflecting the effects of appliance energy-efficiency improvements.The method makes use of a three stage transformation process which firstcreates seasonal variations of individual monthly data, then converts the lowresolutionhourly data into high-resolution minute data and finally projects thedata into a high efficiency scenario reflecting improved appliance energyefficiency.ii. Characterisation of the thermal demand in a building through the modelling ofthe building characteristics and the internal heat gains. The research describeshow, the characteristics of a typical Maltese multi-family residential building(including aspects such as building geometry, fabric, shading etc.) weremodelled through the use of the building simulation tool ESP-r, and how thesame building fabric and geometry were then modified to include for changes inoperating conditions which could possibly impact micro-trigeneration systemperformance. With regards to the internal heat gains, a process leading to themodelling of high resolution internal heat gain profiles due to occupants andappliances was created by combining known occupancy and electrical demandprofiles.iii. Developing a detailed yet easy-to-calibrate model of an absorption chillercapable of capturing dynamic behaviour. The model developed in this researchrelies on a novel approach whereby, it can be easily calibrated as a single unitusing measured data of the inlet and outlet temperatures of the three watercircuits flowing in and out of the chiller, without the need for invasivemeasurements. The model which was built using a system of three controlvolumes each characterising the thermal mass corresponding to one of the water241
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University of StrathclydeDepartment
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ACKNOWLEDGEMENTSIt has been a long
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ABSTRACTThe domestic sector account
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TABLE OF CONTENTSACKNOWLEDGEMENTSAB
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2.4.3.3 Aggregated loads frequency
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4.1.1.1 Factoring for electricity g
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5.5.1.2 Present worth assuming a va
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LIST OF FIGURESFig. 1.1 Separate ge
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Fig. 2.38 Aggregated DHW draw profi
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Fig. 5.23 PP for Scenarios 1 and 2
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uilding 95Table 3.5 Control scheme
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ACRONYMS & ABBREVATIONSBMS Building
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CHAPTER 1INTRODUCTIONChapter overvi
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uildings, and Directive 2006/32/EC
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Micro-cogeneration can make use of
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offer reasonable and adequate retur
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system in a residential building, i
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conditions have on the performance
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effective manner. The research in t
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investigate how a residential micro
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Table 1.1 also includes additional
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1.7 Chapter References[1] DG for En
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[18] Pehnt, M., Cames, M., Fischer,
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[39] Cardona, E. and Piacentino, A.
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[56] Shin, Y., Seo, J.A., Cho, H.C,
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2.1 Modelling residential demand -
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minute resolution data. The researc
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2.3.1 Example: specifying the build
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Table 2.1 - Dimensions of the model
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In this second enlarged building, t
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Table 2.3 - Main characteristics of
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Table 2.4 - Main characteristics of
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esolution demand data for individua
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the original data (see equation 2.1
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the course of a year. The end resul
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specific appliance at a particular
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consumption during this period is e
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awarded on a random basis following
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Table 2.7 - Scaling factors for the
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NVF values for washing machines, el
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Table 2.10 - Annual electrical ener
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2.4.4 Creating the profiles used in
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Fig. 2.16 - Electrical demand profi
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Fig. 2.19 - High efficiency electri
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2.4.4.3 6 Household buildingAs ment
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2.29 and Figure 2.30 show the resul
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period [11].In order to improve on
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(as discussed by Richardson et al.
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similar fashion to the modelling of
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observed measurements from a number
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Fig. 2.37 - Total internal heat gai
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comparing water consumption related
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various aspects which make up the h
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natural Resources" - (LN 238 of 200
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in Domestic Appliances and Lighting
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[49] DEFRA (2010). "Dishwashers Gov
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CHAPTER 3MODELLINGMICRO-TRIGENERATI
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the same research also suggests tha
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cooling device in conjunction with
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simulation tool ESP-r by explaining
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Fig 3.2 - Basic micro-trigeneration
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3.2.3 Control strategies for the pl
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or decrease the flow rate of the co
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efrigerant, which in this case is w
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arbitrary cycle configuration, usin
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coefficients for the future and pre
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Applying basic energy and mass cons
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CH Power , the chiller’s refriger
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general form of equation (3.16) [33
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functions of hot water circuit inle
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circuit were obtained and how the p
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the internal high and low pressures
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the imaginary boundary constituting
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the model was then compared to a se
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Fig. 3.9 - Modelled chilled water c
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standard deviation was calculated t
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The selected tank size is based on
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3.5 Summary of Chapter 3This chapte
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Conservation in Buildings and Commu
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uilding simulation." Doctoral Thesi
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CHAPTER 4SIMULATIONMETHODOLOGYANDAN
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Table 4.1 - Scenarios investigatedS
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The building fabric, building size
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analysis in the case of the interme
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micro-trigeneration system are thos
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profile for that same time period (
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4.2.1.3 Calculating the fuel consum
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cogeneration technologies [16].- (4
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the present 1.088 kgCO 2 per kWh de
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Table 4.4 - Explanation of the cash
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FIT and considering the cost involv
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impact they have on the energetic,
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Conservation in Buildings and Commu
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CHAPTER 5RESULTSANDDISCUSSIONThis c
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increases so does energy-efficiency
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the building fabric is most effecti
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Instances where the load duration c
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households, GF refers to the ground
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Finally, and this will be the discu
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In the table, the low and high effi
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The scenario with the lowest number
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Comparing Figure 5.3 and 5.4, respe
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number of cycles during the cooling
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5.3.3 Chiller’s performanceAs dis
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5.3.4 Electrical performance of the
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decrease in net imports and net dem
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Page 218 and 219: Table 5.11 - Micro-trigeneration pr
Page 220 and 221: The PES obtained for the different
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Page 224 and 225: Similar results are obtained for al
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Page 228 and 229: Fig. 5.8 - Sensitivity of Emissions
Page 230 and 231: Similarly to the effect on PE SEPAR
Page 232 and 233: 5.5 Micro-trigeneration system econ
Page 234 and 235: As electricity costs increase (rela
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Page 244 and 245: Fig. 5.17 - CF and CF component ter
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Page 252 and 253: Similarly to the PW and the IRR, it
Page 254 and 255: Table 5.13 - Summary of micro-trige
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Page 260 and 261: micro-trigeneration system. Convers
Page 262 and 263: CHAPTER 6CONCLUSION:OUTCOMESANDFUTU
Page 266 and 267: circuits associated with the absorp
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Page 270 and 271: plant models using the building sim
Page 272 and 273: APPENDIX AEquation factors for sele
Page 274 and 275: Factors for use in equation (2.1) f
Page 282 and 283: APPENDIX BElectrical demand profile
Page 284 and 285: Fig. B4 - Current efficiency electr
Page 286 and 287: Fig. B10 - High efficiency electric
Page 288 and 289: Fig. B16 - Current efficiency elect
Page 294 and 295: Component ESP-r Database: Annex 42
Page 296 and 297: 0.0000 #88 Performance map: Thermal
Page 298 and 299: 99.999 #1 Evaporator Total Mass (Fl
Page 300 and 301: 100.00 #13 Boiling temperature of f
Page 302 and 303: One way to solve a partial differen
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Page 308 and 309: &COMMON/PCOND/CONVAR(MPCON,MCONVR),
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C Calculate T1 (DegC): T1 = ((T16-T
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XST=4010 DST=-(9.133128) + (0.94396
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& + 2500.559)*1000C Refrigerating p
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End IfC Calculate h3 (J/kg): h3=h2+
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&&ElseEnd IfActPow=0ActPow = PCONDR
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C Node 1, thermal mass effected by
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WRITE(ITU,*) ' Connection(s) ',ICON
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Fig. F.1 - IRR for scenarios with d
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Fig. F.5 - PP for scenarios with di
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PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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