Passive Cooling Techniques to Keep Buildings Cool in Summer

Now that the summer is around us, people will start switching on their environmentally hazardous air conditioners in homes. These energy-hungry air conditioners are the major contributors to climate change. Though we cannot deny the fact that they make it so much easier to spend our summers; we also cannot ignore the numerous disadvantages they provide to our environment as well as to our health. Not to mention, they cost a lot, so not everyone can afford them.

Passive Cooling Techniques for Building

However, air conditioning isn’t the only way to get by the summer with ease. Since ancient times, architecture has always been able to combat the scorching summers. Before the days of air conditioning and other artificial cooling appliances, there were techniques that helped people get salvation from the hot summers.

In architecture, we call these techniques “Passive Cooling”, which is a building design approach, focusing on reducing the heat gain of a building. There are few natural methods to cool the internal temperature of a building, as well as save on energy bills. Passive cooling depends on the design of the building, like the building orientation, fenestrations, etc. Simple passive cooling covers all-natural techniques of lowering the heat gain and modulation without the use of energy. Below are the passive cooling techniques that designers should approach in the buildings.

Passive Cooling Techniques to Keep your house Cool

1. Cross ventilation

It is a natural method of cooling, which forces hot air inside to your to move out and take the dust and pollutants with it. By providing cross ventilation, you can keep the air from staying still, avoiding it becoming stale and warm.

Providing cross ventilation by including 2 or more windows

2. Stack Ventilation

Apart from cross ventilation, stack ventilation is also an effective cooling strategy. Unlike cross ventilation, this ventilation creates airflow using the natural force that emerges from changes in air pressure, temperature, and density levels between corresponding internal and external environments.  

Providing Stack ventilation for Hot Air to escape

3. Site orientation

The orientation of the building should be according to the sunpath as well as the microclimate. Normally, the north direction gives off the best sunlight with less glare and UV rays. However, the opposite can be said about the south direction. Therefore, lesser fenestrations should be used in the south direction.

Orienting the site to ensure the building is not exposed to too much sun in summer

4. Night Flush Cooling

Night flushing is interesting natural ventilation that uses the effect of the night and the cooler air at night to circulate inside the building and decrease the heat gained during the day. Typically, you can use this method by keeping the building envelope closed during the day.

This is results in the thermal mass of the building mass acting as a sink through the day and then absorbing the heat gains from the users, roofs, walls, electrical appliances, and so on. Finally,  at night, when the outside air becomes cooler, opening the fenestrations will allow the cool air to pass through the building and then pushing out the hot air stored inside.

5. Evaporate cooling

You must remember from your school textbooks that evaporation of water causes a cooling effect. So, this passive cooling technique uses this principle of evaporation as the main idea behind cooing buildings. This technique can simply be used through a water feature, such as a pond in your garden or roof pond, swimming pool, fountain, and so on.

using water ponds inside the homes to cool the place through evaporation

6. Light colored Roofs

We all know that dark colors are great heat absorbers. So, using light colors such as white, cream, beige, etc, is highly suggested when living in a tropical climate. Roof affects the internal temperature of your home, as it directly allows the building to gain heat from above.

Light-colored roofs reflect away the heat rays from the sun, allowing minimum heat to pass through the roof. Whereas, dark-colored roofs just do the opposite. You can increase the reflective properties of light-colored roofs by applying a highly reflective type of paint that is available in the market.

Light colored roofs to reflect maximum sun light

7. Plants

Whether indoors or outdoors, plants are an incredible way to beat the summer without air conditioning. They not only enhance the quality of air but also keep the building cool as they lose water during transpiration. This phenomenon allows the plants to cool the air around them, leaving them purified and fresh.

Maintaining Indoor Plants to cool the rooms

8. High Ceiling

It is a common concept that hot air is lighter than cool air, thus hot air always stays at the higher level while cool air stays below. High ceilings give more volume to the building for fresh air to circulate and maintain your internal temperature.

Increasing height of ceilings so that hot air raises up

9. Rammed earth walls

Rammed earth walls are thicker than the usual R.C.C. walls. Thick walls provide higher thermal mass to the building. Therefore, they don’t absorb the heat from the outside. The thickness and density of rammed earth walls mean that the heat or cold penetration of the wall is very slow. So, this technique is great for both hot and cold climates as they keep cool in summer and warm in winter.

Rammed earth ready walls are used in the construction of building

10. Natural Building Materials

Natural materials such as stone, bricks, or concrete, have very high thermal masses. As mentioned earlier, materials with high thermal masses are a great way to keep the outside air from entering, both cool and hot. The amazing ability of these materials to absorb heat slowly reduced the temperature of the building.

Use of thermal insulated materials for building construction

Unlike today, in old times, special attention was given to cooling techniques while constructing the buildings. Design elements such as courtyards, pergolas, overhangs, and large casements were widely used to cool down the building in times of no electricity. Unfortunately, these age-old practices are now being overlooked with the arrival of quick and effortless cooling appliances.

Nonetheless, with climate change, the world is slowly resorting to sustainable techniques, which include the above passive cooling techniques. Though the effect is not huge, within time, these sustainable designs will completely overshadow the conventional buildings, inspiring other designers to do the same.

– Tulisha Srivastava