Passive Design Strategies for Tropical Climate

Tropical climates are characterized by hot, humid summers, high moisture, and little difference in temperature between day and night. Air movement is an important cooling strategy because the body finds it more difficult to cool itself through sweat in damp surroundings. In order to maximize cross ventilation and convective air inflow, the most pivotal passive design strategy in the tropics is to keep structures as open as possible, even during the hottest part of the day.

When designing in the tropics, the kind of windows used and where they’re placed are particularly important. By meticulously placing windows, it’s possible to achieve the ideal level of thermal comfort. All of this is possible without the use of air exertion.

You can achieve your pretensions for thermal comfort by carefully choosing the materials when designing. These materials will dictate how heat transfers into your home. Incorporating outdoor spaces that offer great functionality is also an asset.

When designing in the tropics, you should take into account a few essential principles.

  1. Orientation
  2. Shading
  3. Wall Materials and Construction
  4. Ventilation
  5. Other Factors

1. Orientation

  • How well your Structure takes advantage of the prevailing winds and guards against sun exposure depends on its orientation on the site. Your project’s location in the world will affect these variables.
  • The longer side of your structure should ideally be oriented east to west when designing in the tropics. The exposure to the morning( east) and evening( west) sun is minimized by this orientation.
  • The sun’s heat can be extremely hot and violent, particularly in the evening. Additionally, they’re challenging to shade because of the sun’s low angle at those times.
  • It’s best to place your structure to take advantage of the dominant winds. When designing in the tropics, you should allow as much wind as is comfortable to pass through it. Prioritise rooms that need the utmost ventilation and locate them towards prevailing winds.
Building Orientation
Building Orientation

2. Shading

  • The quantum of heat gained inside the structures will be greatly reduced if the direct sun is averted from entering.
  • Shading from the sun prevents walls and other surfaces from heating up and transferring that heat to interior spaces.
  • Horizontal shading is ideal for both the north and south- facing walls and openings since the sun is at the topmost point in these directions whereas vertical shading approaches should be used in the east and the west direction since In the mornings and evenings, the sun angle is low.
  • Patios and verandas are excellent for providing midday shade for northern and southern walls.
  • To prevent solar heat gain on walls facing east and west, vertical shading should be provided by screens or vegetation. Because mornings are generally cooler, the evening sun appears hotter than the morning sun.
  • Additionally, large trees can offer general shading to your home’s exterior and the areas outdoors, allowing for cooler indoor air temperatures.
SHading in Buildings
SHading in Buildings

3. Wall Materials and Construction

  • Heat transfers from structures primarily take place through the structure envelope, windows, and ceilings through conduction, convection, and radiation.
  • Marble, gravel concrete, and asphalt are good heat conductors and should be avoided in external construction, whereas materials that transfer the least quantum of heat from outdoors to inside, such as certain types of glass and wood, can be used for walls, ceilings, and windows to produce a cool interior.
  • Additionally, openings serve as a heat-transfer medium.
Wall Materials and Construction
Wall Materials and Construction

4. Ventilation

  • For your structure to maintain a comfortable interior temperature, there must be an uninterrupted flow of air. Utilizing the cross-ventilation method will help you generate this movement.
  • Each room should ideally have at least two openings, and they should be on two different sides of the space. Additionally, you should place them so that air circulation is promoted in all areas of the space, not just one corner.
  • Since clearstory windows make it simple to remove hot air, we can also take that into consideration.
  • Another benefit of this is that cool air is drawn into the lower level through windows as hot air escapes from the higher level. This process is called the stack effect.
Cross-ventilation in Buildings
Cross-ventilation in Buildings

5. Other important factors 

  • Using light colors and adding reflective elements to your exteriors will reduce the heat gain of the structures.
  • Sun will also be filtered by using foliage to give partial shading rather than just as part of the landscaping.
  • Thermal comfort can be achieved by meticulously planning the landscape, using dehumidifying trees, water features, etc. where necessary.
  • The use of elements like eyebrows, jaalis, and tilted walls to give self-shading, and overhangs, is also seen in some structures.

Along with the problem of extremely high temperatures, the tropical area has many other problems. Because these areas use a lot of electricity to run air conditioning units and other climate-control equipment, the air quality is poor. Additionally, the glare issue is generally disregarded. In order to regulate the interior temperature, numerous structures have entirely glass facades, but the reflections from those walls raise the temperature outdoors. As designers, it’s our responsibility to address these issues and create habitable spaces that have little to no negative impact on the area or the people who live there.

No Footprint House, Costa Rica

A tropical rainforest surrounds this house, which is situated along Costa Rica’s western coast. Even though it is situated in a humid and unsettling environment, the house’s design uses some of the passive design techniques mentioned above to help create a habitable and pleasing living environment.

  1. The architects were able to create an open floor plan with plenty of air circulation throughout the building by integrating all necessary amenities like the kitchen, bathrooms, and closets into the central core.
  2. It has a double-layered envelope where the outer face filters out the sunlight as it is inclined outwards creating a natural self shading system along with a little help from the operable panels. 
  3. The scenic view is captivated by the panels creating a visual experience as they integrate the beauty of the landscape around the house into the interiors.
  4. While the house is supplied electricity by the public service grid which is powered by renewable energies, the roof is used to harvest sunlight. In turn the energy was used to heat water.
  5. This kind of critical thinking and execution capabilities is something to reflect on as architecture takes a new direction by not only thinking about its users but also the impact it causes on the environment.
No Footprint House - Photography: Fernando Alda
No Footprint House – Photography: Fernando Alda
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