geoff pyle seminar
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Geoff pyle seminar at Manolis House. http://www.pylearchitects.com/ manolishouse.wordpress.comTRANSCRIPT
Building ‘green’ in Cambodia
Architectural principles andpassive systems
Geoff PylePyle Architects
9 November 2010, Manolis House, Phnom Penh
Green is one issue among manydesign criteria
Green design fundamentally affectsthe building
Green is more than just energy…
Five groups of issues
1The Site
Current use of the land.Transport to and from.
Control of pollution, includingduring construction.
Solar reflectance and ‘heat-island’effect.
2Water
Rain water absorption and run-off.Processing of sewage drainage.
Collection and reuse of rainwater.
3Materials
Embodied energy.Recyclability.
Waste (during construction and use).Sustainable timber.
4Indoor environment and health
Air quality.Pollutants.
Daylight and views.User control of environment.
5Energy
Minimise energy demand through design.Lighting and cooling (design of building
envelope, and efficient systems).Water heating.
Renewable on-site generation may bepossible.
Pre-designThree questions to ask…
1In designing green, where will we place
our emphasis?If we cant do 100% of everything, what
do we prioritise?
This has to be decided for each project.
2Are we going to assess how green we
are and if so how?
Will we do comparisons of carbon/energy/cost?
3Will we validate it through an externalorganisation and get a certificate of
green-ness?
Possible benefits: assurance that green is thorough;most effective for capital investment; and marketing
advantage.
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Passive and active systems
Outline approaches totemperature and the building
envelope…
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No air-con : basics - what creates thermal comfort?
1 Shade from direct sun
2 Limit radiant heatfrom surfaces nearby(insulation?).
3 Evaporative coolingfrom skin through airmovement (fans orwind) assisted bywater/plants if possible.
Note: these slides show broad general principles, whichshould be reviewed in particular design situations…
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No air-con : insulated roofs (either flat or sloping)
Insulate roof to‘cool’ the innersurface andreduce radiationinternally
OK
Roof heats up;radiation from roof
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No air-con : insulation plus double roof
OK+ Better than justinsulated singleroof
Only 50% of originalradiation is emitteddownwards
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No air-con High double roof
OK
Due to distance betweenroofs, effect of radiation isreduced, so no real benefit ininsulating lower roof
Only 50% of originalradiation is emitteddownwards
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No air-con : walls similar in principle to roofs
OK No need toinsulate if nosun on wall
Sameprinciplesapply to wallswhich areexposed to sun
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No air-con : natural cooling at night may be effective
Night cooling ventilationthrough floors may be possible
Cross-ventilation; cooling the thermal mass of structure (concrete)at night - the concrete cools the space the following morning
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Air-con : typical - minimise heat gain from outsideAir tight jointsto prevent airleakage
Insulation
Limit electriclights by useof daylightDesignwindowscarefully
28C-35CRH 70-85%
23C-25CRH 50-60%
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Air-con : how to do windows
Clear glass : about 80% ofheat is transmitted
“The real cost ofremoving the heat thatenters a buildingthrough the windows isso great that it iseconomic to spendconsiderable sums ofmoney to reduce solarheat gain.”D G Stephenson, NationalResearch Council Canada
Insulated wall : less than5% of that through clearglass
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Air-con : how to do windows
Blind heats up and radiates - noteffective in keeping out heat
Convection around the blindalso brings heat into the room
Blinds are good for controllingglare but not heat…
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Air-con : how to do windows
These are better thanclear glass but costmore, and can reducedaylight, increasingdemand for electriclighting.
Not as effective asSHADING by a longway.
Options for glass:• Reflective glass• Heat absorbing glass• Double glazing• Low-E coatings• Gas-filled• Combinations
Glassheats upandradiatedsfrom bothsides
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Air-con : how to do windows - shade
Note: if shaded,coloured glass isof no benefit.
Consider alsodouble-glazingand low-Ecoating for betterperformance.
Many options forshading glass/walls.
Use sun pathstudies and videomodelling.
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Interior quality for users: daylighting, views, glare.
Designing a Building Envelope to be ‘green’ involves bringingtogether:
Image of the building for the owner, both in terms ofstyle and how ‘green’ the building is seen to be.
Budget and materials available.
External factors: orientation, climate, noise.
Cost-benefit analyses of different approaches -and understanding how extra capitalexpenditure is to benefit operating costs.
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Briefly on materials
Generally:
Consider the ‘whole-life’performance and cost.
If higher-carbon materials last a lotlonger - they may be more cost-effective AND more sustainable.
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Briefly on materials
Insulation:
Various types available in the international market, somemore ‘green’ than others. More coming to Cambodia.
Buy as ‘green’ a type as possible, but even if not, it isbetter to insulate well - to lower energy use.
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Briefly on materials
Structure:
Steel not used so much in Cambodia, butis recyclable unlike concrete, and is moreeasily adapted.
Concrete is being used overseas nowwith low-carbon cement substitutes,which reduce the amount of cementneeded.
For every ton of cement produced,approx. 1 ton of CO2 is produced fromchemical reaction and the burning offossil fuel.
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Case study: residential resort in Siem Reap
WATER STORAGE UNDER BUILDING
SEWAGE TREATMENT UNDERTENNIS COURT
Rain water holding tanks reduce load on city mains drainage and allow use for irrigation.Sewage treatment on site means ‘clean’ water is discharged to city main drains.
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Case study: residential resort in Siem ReapWindows are shaded by balconies. Plants and trees refresh the air and lower temperatures.
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Case study: residential resort in Siem ReapApartments and stairs are naturally ventilated, in ways which provide security.Roofs and walls are insulated. Hot water provided by solar panels. Air-con is ‘efficient’ type.
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Case study: Hun Sen Library extension at RUPPMainly naturally ventilated, with some air-con spaces. Uses existing trees for shade and toprovide confortable outside spaces for students.
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Case study: Hun Sen Library extension at RUPPMain reading area lit by daylight through glass with sun-screens (trees not shown here)
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Case study: Hun Sen Library extension at RUPPMain reading area lit by daylight through glass with sun-screens (trees not shown here).Ground floor is open for use by students, with view of water.
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Case study: Hun Sen Library extension at RUPP
Air-con spaces shown blue.
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Case study: Hun Sen Library extension at RUPP
Holes in floor allow a little more night-time cooling…
Building ‘green’ in Cambodia
Thanks