3 Passive Cooling Techniques in the Tropics

Remidelle Alimbuyao
27/08/2020 2:37:43
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The warm light of the sun, abundance of fresh breeze and all the natural resources it could offer, truly, the tropics is one of the best places to place your roots and settle down. The tropics is the sweet spot, where biodiversity is at its peak where two-thirds of the world’s species are thriving.

One of the best ways to create a perfect home is to create it with respect to the natural elements acting up around it, good architecture exists in harmony with nature. Passive Cooling does not only give user comfort, but it also saves energy making the house sustainable. There are a lot of passive cooling techniques but here are some that can be applied to your future home in the tropics.

1. Stack Effect or Chimney Effect

Warm air goes up, cold air goes down. That is essentially the thought of stack effect, the density of colder air is greater than the warm air. In the tropics where air inside is commonly colder than outside Stack Effect works when warm air intake from outside are as low as possible and the ceilings are as high is possible. Vents that let the warm air escape to the top of the building decreases moisture accumulation and air pressure inside the house while windows’ placement and size should be able to accommodate more cold air intake rather than warm air.(Ibrahim, Rohaida Affandi, Mohd Nasrun Mohd Nawi)


Figure 1. A diagram of air flow in a space where stack effect is disregarded compared to a space where it is designed with respect to basic principles of air movement. Edited by Remi, CIPD’s Architect Intern.

2. Building Orientation (Sun and Wind Pattern Study)

Sun rises to the east and sets to west. Building orientation in the tropics is critical to achieve user comfort and avoid excessive use of mechanical cooling which costs a lot of money in the long run. The best orientation for building in tropical climate is facing north-south and facades are east-west facing the sun with medium to minimal opening fixed windows or else it will be too exposed, heating up the building in the process. It is also important to place spaces in relation to how much sun should it take in (Apis, 2012).

For example kitchen, dining and laundry areas are advised to the rays of the sun, lounging spaces are placed where there is sun but not as much to make it uncomfortable to lounge in, and sleeping places should be cooler in order to induce sleep and rest so it is not advised to place it where the sun rays penetrates the space fully. If their site does not allow this type of orientation, some remedies can be done such as the correct length of eave, correct placement of fenestration (windows must be 15-20 percent of the total floor area) and the usage of existing trees on site to manipulate cooler wind to circulate (Mishra, 2014) .


Figure 2. An illustration of a recommended orientation of a home in the tropics. The position of the house tilts to where the Amihan (North-East Winds) and Habagat (Southwest Winds) can penetrate the whole structure so that there is air circulation all year round. (Pinterest, 2020)

3. Choose your windows wisely.

In tropical climates it can get hot really fast, humidity is very high that is why it is important to choose the design of your windows and openings that best suits the climate where your house is located. It is traditionally used by the locals, windows that control sun penetration while at the same time allows ample air flow. Windows such as awning, sliding and casement are advised, however, the best type of window for tropical climates is the Jalousie.

Jalousie Windows or Louvre Windows can adjust the amount of airflow during rainy season as well as sun radiation during sunny seasons without compromising user comfort, it is also important to find a quality supplier of these windows with proper sealing and durable panels.

However, western influence has greatly affected the design of homes in the tropics and the result is predictable: Wide and enclosed glass windows overexposing the interior to the sun’s radiation with zero air circulation during both seasons heats up the interior of the house and that increases energy consumption because users will resort to using air-conditioning units. This wastes the ample natural wind circulation that the tropics offer.


Figure 3. A diagram of airflow percentage on different types of windows. (Breezway, 2020)