Sustainable Design FAQ/ guide Index:
The previous chapters outlined the basics of sustainability within tropical climates and presents some theoretical approaches towards sustainable or energy efficient high rise construction while considering the realities of the present market conditions. In this chapter we look at a typical residence. Low rise, single family home. In some developing countries these are marks of prestige. The ability to have a custom home designed and built to their requirements. This obviously happens to be one of our specializations, therefore it would be remiss if we did not at least address this particular building type.
Sustainability in the tropics: A Return to Vernacular Architecture.
Applying designs across the pond without paying proper attention to climatic concerns is asking for trouble. Sustainability is important and will gain more prominence in developing nations over the next few years. With the ever rising cost of energy, it's not something any nation can avoid. Buildings do take a lot of energy to build and maintain or operate. However as stated before, it's not about implementing sustainable techniques that work well in another country. Take a look back in history and how the old "wet" markets were laid out as opposed to those built around newer Malaysian or Singaporean communities in the 80's and 90's.
The newer markets with stacked floors and low ceiling heights operated like ovens in the humidity and sun of Malaysia. Cross over to Singapore and you see the same thing with the newer markets there too, built on the ground floors of high rise residential buildings. However in older markets with higher roofs (& cathedral ceilings), there was better stack ventilation and cross ventilation. Smells were kept in control and heat buildup was minimized. Hot air managed to escape by rising to the top of these high roofs and being vented to the exterior.
These designs drew from traditional and vernacular architecture. The Malay homes indigenous to the "kampung" or village. Looking at aboriginal ("orang asli") architecture of the "Long house" of the Murut, or Kadanzan Dusut tribes, you will note similarities in using elevated buildings, high steep roofs and lightweight building materials. All designed to promote ventilation, natural daylighting and cooling.
Obviously with development comes change in the way buildings are designed and built. New homes can be built using these fundamental principles to help maintain indoor air quality and comfort. Sometimes drawing from the past, you can come up with some very new and innovative designs.
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Sustainability in the tropics: Low Rise Residential Strategies.
These pages should be treated as a whole. Including the initial two pages of the sustainable design FAQs. Page two defines different alternative construction methods and by looking at those strategies, it is possible to develop a sustainable design incorporating many of those ideas, along with other methods like earth berming, or earth tempering/ coupling and vernacular design. Modern contemporary designs or traditional designs can be formed by these very ideas.
It was recently reported that a village in Thailand was re-built using volunteers and Cob construction. It still remains to be seen how well the Cob walls will hold up under monsoon rains but the ideas behind are sound. Using a natural material that is cheaply and widely available. If protected and detailed well, there is no reason why those walls would not hold up. Cob construction has been around for a long time and there are many structures built from earth that are still standing after several centuries. That is a better track record than your typical wood stud framed building.
Burying a building or berming earth up against it are not new concepts. Managing the moisture and controlling water penetration is important and should be combined with natural ventilation. Doing the inverse of geothermal heat (geo cooling) but using a active system that loops a substrate through coils buried within the earth has its merits. This involves using the earth as a heat sink to draw heat away from the interior of a building to dissipate it within the earth. You are not going as deep as geothermal would require.
A similar concept would involve pouring a thicker concrete floor slab on grade, which would tie into the earth and use it as a heat sink. Radiant floor cooling utilized as a passive system as opposed to an active radiant cooling floor that utilizes mechanical means to cool the floor. The concept of cooling surfaces rather than forced air works better for human comfort or perception of comfort.
These concepts can be applied to large scale mass housing tracts. Instead of grading entire hillsides flat to build rows of Terrace/ Row Houses, the communities could be plan to follow the contours of the land. Orienteering the blocks to maximize natural ventilation, daylighting but avoiding heat gain from both east and western sun exposures. Using the contours may enable the homes to utilize berming as a way to temper the indoor temperature by using the earth as a heat sink.
Sometimes it's not about a single solution but a number of complementary features that enable a building or home to be comfortable and sustainable. Designing in stack ventilation by drawing from traditional forms enables a home to breathe, so to speak. Hot air rises to the top and is drawn out of vertical elements/ towers or stacks, allowing cooler air to enter the building at a lower height. Sometimes, we can extrapolate these ideas further by looking at nature itself. Some have liken the technique of stack ventilation with the way termites in the desert use a series of tunnels to help keep their mounds cool.
We can draw from nature within tropical countries to evolve designs that are sustainable and promote cooling with little or no active energy requirements. We can learn from the mangrove swamps and canopies of dense tropical rain forest. Studying the physical characteristics of successful fauna in tropical environments can help us develop better design concepts that are more appropriate for tropical climates. At GLA, we are developing several concepts we believe are feasible for production housing in asia, implementation in single family residences and or low rise commercial structures.
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Sustainability in the tropics: Conservation
Drawing from the past,in older homes throughout Asia and which can sometimes still be witnessed, the collection of rain water from the roofs remains a common practice. While the present global crisis seems to be focused on oil and energy, there is a new crisis looming. The shortage of potable water. The availability of potable running water in plumbing within homes is still relatively new in many Asian countries. However the quality of the water still tends to be an issue. Having said that, treating water for public consumption remains a high costs item to most of these developing countries. It makes sense to develop system to minimize the use of potable water for plumbing needs or requirements that don't really need treated potable water to function.
Why flush perfectly good drinking water down the toilet? While the housing stock of developing countries are growing at a prodigious rate, they have not reach maturity yet. There is time to implement systems that are cost effective and would help nations save a considerable large amount of money by lowering their water treatment loads. Implementing dual plumbing systems in homes is still viable. Many of these countries have heavy rainfall throughout the year. A dual plumbing system could be implemented where rain fall could be collected in cisterns or secondary water tanks (many homes already have a primary water tank standard). There are obvious uses for collected rain water which is untreated or unfiltered. The flushing of toilets comes to mind and so does irrigation if necessary. A simple filter system could be used to enable collected rain water be utilized for laundry and other washing needs that do not require treated water. Asians tend to wash their homes on a regular basis, using potable water for that, makes little economic sense.
Should there be a shortage of rainfall during the drought seasons, a simple flip of the control valve enables the regular water system to be utilized for these services. There are cost implications for having a dual plumbing system in the building but it will probably be offset by the long term costs savings. If governments and water utilities were involved, these could be offest by rebates to consumers or builders.
Recycling of waste should be given a higher consideration instead of the typical mode of using landfills in developing countries.
Using separate bins for recycling paper and plastics/ metals is a fairly common practise in many countries and should be promoted
within each society.
For high rise residential towers, there is now the option to have a single waste chute but an automatic separator at the lower
portion that can divert paper and plastics from organic waste.
Sustainability and recycling needs buy in from the authorities running waste management districts and governmental authorities. Having separate bins allows for the use of smaller waste management vehicles that are coordinated to pick up different types of waste. Organic waste tends to the heaviest and bulkiest, thereby requiring heavier vehicles. Paper, metal and plastics materials could then have a separate vehicle that takes the materials to a recycling station or facility.
Recycling can help decrease our reliance on landfills and in small countries with limited areas or resources, would reduce the pressure on agriculture or arable land and the amount of imported raw materials.
Sustainability should be approach in a holistic manner. Recycling, energy efficiency, Co-generation (using waste as fuel) and other techniques, should all be seen as part of a comprehensive approach to creating better communities.
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The effort to bring sustainable design and buildings to developing countries in Asia needs to be heightened. Developing countries in their haste to reach developed status, need not necessarily repeat the same mistakes of developed nations. Sustainable growth enhanced or complemented by sustainable buildings should help these nations cut costs and lower their operating costs. It leaves that much more money for development.
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