The GreenHouse Project's Adventures + Lessons in - ELLEN ...

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properties, as well as having low embodied energycompared to other insulation products. It requires lowlevels of a boron additive as a fire, fungus and insectretardant. Boron has a low to moderate toxicity forenvironment and health. Cellulose loose fill can be usedin the ceiling, piped into cavity walls or stud walls foracoustic and thermal purposes. Workers must wearrespirators to prevent breathing in the fine dust whenapplying the insulation. It is suitable for many domestic,commercial and industrial applications.Solar cooker and free standing ‘Sunstove’Solar cookerA built-in solar stove wasmade by CBS Architects,adapted from designsfor portable units. Solarovens are a simple, nonpolluting,inexpensiveway of cooking food withsunshine. They can beeasily and cheaply built.The one at the GHP was built using galvanised steel,insulation and a brick base with a firmly fitting woodendoor so that heat is retained. The sloping, shiny metalsides concentrate the sun’s rays at the centre of thecooker. The glass cover is stuck to the cooker walls withsilicone (which serves as a strong, waterproof glue). Thewooden door through which you move food in andout of the oven is accessed from the reception area ofthe office. (For more information see the fact sheet in theappendix).Free standing ‘Sunstove’The GHP has acommercial ‘Sunstove’that can be carriedoutside on sunny daysfor use. This lightweightstove opens in front andis effective and userfriendly.Some 10 000 SUNSTOVES® have been sold to southernAfrican users. The SUNSTOVE® is aesthetic and rugged.It cooks for six people, yielding four to five litres ofmealie-meal or rice with one to two litres of vegetablesor meat. For over seven years it has been massproduced in lots of 1 000 at a cost of $20 each in SouthAfrica (around R150).Lessons1 According to CBS, the solar cooker has proved tobe a far more useful product and a better investmentof time and materials than the water tanks.2 The cookers are not used to their full potential,partly because of the power of habit anda certain mistrust of solar cooking. Peoplehabitually cook on open fires or conventionalstoves because it is familiar and secure. A dailystaple at the GHP is traditional maize porridgeand France Maleme, administrator at the GHP,says that the built-in solar cooker does not allowfor easy, in situ stirring, so the porridge is notcorrectly cooked. Education is very important ingetting people to break old habits.Sod roofA sod (earth and livingplants) roof providesinsulation above thekitchen, bathroom andstore area at the GHP.The building is protectedfrom the wet earth aboveit by a bitumen andaluminium waterproofpaint layer and a geofabriccalled biddum.The latter is made ofpetrochemicals and doesnot degrade. Two yearsago, when the pottingshed was built,alternatives were not available. However, CBS Architectshas since learned of hemp fabrics and also ‘Bio Jute’ soilblankets (made by Maccaferri and available in SouthAfrica from African Gabions).The biddum was laid on the painted concrete andthen covered with gravel. Drainage is provided allaround via gargoyles which are made of half clay pipesand slope downwards to direct water away from thewalls and windows.Roof plants include drought resistant Seneciomacroglossis and bulbinella spp.Education is very important in getting people to break old habits.26 The GreenHouse Project
LessonThe GHP sod roof was a complex and expensiveexercise for the small amount of garden it yields.Its contribution to energy efficiency is limitedby the fact that heat is gained and lost throughthree skylights. However, the garden coveringdoes prevent the hot sun from drying out thewaterproofing which typically results in failurethrough cracks.Reflective glass on windowsCompact fluorescent light bulbsCompact fluorescent bulbs are used throughout the pottingshed. Fluorescent lights convert electricity into illuminationthree to five times as efficiently as conventionalincandescent lights. Lamp life is also about 10 x longer.Compact fluorescent lamps (CFL) can be usedin many overhead lighting situations as directreplacements for ordinary light bulbs. A CFL willconsume up to 80% less electricity in its lifetime than alight bulb and could last 12 years if burnt for only threehours per day. An ordinary light bulb converts 95% ofthe electricity into heat and only 5% into light. A CFLprovides the same amount of light from one fifth of thepower consumption. However, some people prefer thequality of tungsten light for desk and reading lamps.Taking into account both product and electricity costsfor tungsten and CFL, the ordinary light bulb guzzlesfive times more electricity and costs four times more forequivalent hours of light delivered. Although CFL areexpensive to purchase, they also have a long lifetime– not one bulb has been changed at the GHC as yet.Natural lightingThe north and eastern windows are glazed with‘Antelior green’. This glass is a 6mm laminated glass witha green film and it is quite a lot more expensive thanstandard glass. Four mm is normal window thickness,while 6mm is used for safety glass.The theory behind the use of Antelior in thewindows of the most exposed facades, the north andeast, is that it controls penetration of sun’s rays sothe building doesn’t overheat on these sides. It alsoprevents some heat loss during winter.LessonIn practise this glass is expensive and for the price,it has a limited effect on the building’s thermalproperties. The glass does, however, have anattractive finish, reduces glare from the morningsun and gives building users privacy.The original asbestos roof on the potting-shed wasremoved by Everite and reclaimed tiles from otherstructures on the site were used as the new covering.The pitched roof trusses were modified to allow aclerestory window arrangement to improve the dimlighting conditions. This enables natural light toilluminate the office on dim days without resorting toartificial lighting.Three skylights have been constructed – one overthe kitchen and one over each basin in the bathroomsto let in much-needed light. They are built as brickedchimneys with north facing sloping glass, which issecured to the ‘chimney’ with silicone. Skylights letin natural light; this means one does not use as muchelectricity for lighting.Adventures and Lessons in Green Building27
Page 1 and 2: The GreenHouse Project’s Adventur
Page 3 and 4: ContentsForeword...................
Page 5 and 6: The South African NGO theGreenHouse
Page 7: Re-use versus recyclingExamples of
Page 11 and 12: Chapter 3:The building processThe p
Page 13 and 14: hadn’t had training. Without the
Page 15 and 16: The Dummies’ Guide to green build
Page 17 and 18: Some of the materials chosen for th
Page 19 and 20: icks on their sides and the insides
Page 21 and 22: Potting shed roofVarious options fo
Page 23 and 24: Attractive red mud, found onsite, w
Page 25 and 26: Low-flow water tapsSelf-closing,pus
Page 27: Chapter 6:Energy conservation strat
Page 31 and 32: Energy discussion and learningThe D
Page 33 and 34: Why was the building so ‘expensiv
Page 35 and 36: Chapter 8:ConclusionsIs renovation
Page 37 and 38: Chapter 9:AppendixThis chapter offe
Page 39 and 40: © The GreenHouse Project, Tel: +27
Page 55 and 56: ContactsThe GreenHouse ProjectPO Bo

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