Asian Architecture| ARC 60403 / ARC 2234 0321577 Foo Wei Min Tutor: Ms. Alia
The Implementation of sun shading strategies
to achieve thermal comfort in 8D House, Bukit Damansara.
Asian Architecture| ARC 60403 / ARC 2234
Research Question
• How does the idea of sun shading from vernacular architecture innovatively adopted in 8D house?
• How does each sun shading strategies act as solution to address heat gain issue in 8D house?
• How does the material of sun shading devices contribute in achieving thermal comfort?
• How does the critical external factors influence the effectiveness of method employed?
• Does the strategies employed help to achieve thermal comfort and what are the impact on living condition?
Introduction
Thermal Comfort
Thermal comfort is the condition of mind that expresses satisfaction with the thermal environment and isassessed by subjective evaluation (ANSI/ASHRAE Standard 55). Satisfaction with the thermal environmentis important because it influences productivity and health.
Passive Design
Sun Shading strategies to resist heat gain in a building.
Ventilation to promote heat loss
*Shading and ventilation work collectively to improve efficiency.*
Shading Devices
Watson and Labs (1983) categorized shading devices into three categories namely solar transmittance of glazing materials, interiorshading and exterior window shades. Solar transmittance is defined as the heat admitting or rejecting characteristic of the glazingmaterials. (As cited in Thamina. A., 2009)
Shading Device
Interior Shading
Solar Transmittance of Glazing material
Exterior Shading
Measures to resist heat gain in tropical climate
• Minimise exposed surface area
• Maximise shading
• Use material with good insulation or heat reflective
• Use material with low U value (thermal transmittance)
• Provide buffer space between exterior and interior
Climate in Bukit Damansara, Malaysia
• Average temperature during hot day: -
min: 31.5 degree Celsius
max: 33.0 degree Celsius
• High relative humidity • High amount of precipitation (rain fall)
Idea From Vernacular Architecture
• Eaves • Envelope • Shading Device
Deep eaves for shading
Allow cooler air for ventilation
Highly insulated and reflective roof to
minimize heat transferred into building
Windows to allow ventilation and to block solar radiation
Innovative Idea
• Deep eaves/overhangs forsufficient shelter
• Reflective and highly insulatedmetal roofing
• Vertical sun screen asshading devices
• Eaves • Envelope • Shading Device
Contextual Respond in shading
• Orientation to minimise heatgain
• Vegetation provide shading
• Gymnasium at lower ground wellshaded from evening sun
• Massing and structure itself asshading device
Solution to Address Heat Gain in 8D House
1) Canopy Roof
Eaves
The large insulated overhanging canopy roof covers the entire building providing shelter and shade.
Material
constructed of lightweight metal deck in a light grey
0.52mm Total coated thickness (TCT)
reflect solar radiation and minimize heat absorption.
Full sunPartial Sun
No sun infiltration
Solar radiation reflected away
Diagram explains relationship between overhang and sun infiltration
2m
7.5m
Section drawing
North-east elevation
External
External
Metal deck 0.52mm TCT
200mm rock wool of 50kg/m3
Parsec reflective foil
Steel Rafter
Air gap 300mmfurther improves heat insulation
Solution to Address Heat Gain in 8D House
Insulationacts as a barrier to heat flow, resist heat gain
Solution to Address Heat Gain in 8D House
2) Sun screen
offset heat radiation, aesthetically pleasure.
2inch by 4 inch vertical metal louvres
Solution to Address Heat Gain in 8D House
3) Surrounding vegetation
Solar radiationCooler air for ventilation
Vegetation shades North-west facadeUse of plantings instead of paving to reduce groundtemperature and the amount of reflected heat.
Solution to Address Heat Gain in 8D House
4) Orientation and Built Form
Properly oriented buildings take advantage of solar radiation and prevailing wind
Lower ground floor and ground floor shaded by the land reclaimed for long stretch of verandah
Evening sun
Shadow casted,Lower Ground Floor Well Shaded
Morning sun
Longer Stretch along North South to reduce heat gain.
noon afternoon evening
Solution to Address Heat Gain in 8D House
5) Internal shading device
Curtain used for interior shading.
Reduce solar radiation from south-east fenestration that serve to catch prevailing wind
To compensate the open plan design for better ventilation
Lam et al (2005) conducted a study to estimate cooling loads and energy use for conditioning due to the heat gain through building envelopes. They investigate the impact of internal shading devices such as venetian blinds on cooling loads and electrical use. Their study shows that use of venetian blinds can bring about an energy reduction of 14%. (As cited in Thamina. A., 2009)
External factors
Factors that influence effectiveness of shading method employed:
• South East fenestration for prevailing wind account high amounts of heat entering the building
(Deep verandah as a solution to this: provide shade and catch cooler air)
• Views: Overlooking KLCC Twin Towers
• Aesthetic Value: Painted black to make the vertical louvres look more prominent.
OverlookingKLCC Twin Tower
Sheltered thus air is relatively cooler
Q5: How does the critical external factors influence the effectiveness of method employed?
Improvements• Longer sun screen to provide sufficient shade
• Avoid façade in dark colour
• trees can act complementary to window overhangs, as they are better for blocking low morning and afternoon sun
proposed for future designs
References
• Chris. R., Paul.D., 2013. Your Home: Design For Climate. Retrieved from http://www.yourhome.gov.au/passive-design/design-climate
• Caitlin. M., 2013. Your Home: Shading. Retrieved from http://www.yourhome.gov.au/passive-design/shading
• Housing for health, 2013. Passive design in tropical zone. Retrieved from http://www.housingforhealth.com/housing-guide/passive-design-in-tropical-zones/
• JTC, 2013. Roofing Contractors: The benefit of zinc roofing. Retrieved from http://www.jtcroofing.co.uk/news/benefits-zinc-roofing/
• Don. P., Donald, P., 2014. Whole Building Design Guide: Sun Control and Shading Device https://www.wbdg.org/resources/suncontrol.php
• Ho, 2015. 8D House.
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