Urbanisation

How we lost the art of manipulating microclimate

The current mass housing construction is in contrast from the traditional urban forms of the city, which had smaller shaded spaces, were more useful and also required lower maintenance

 
By Sugeet Grover
Last Updated: Monday 05 August 2019
The recently constructed urban space in Lucknow bears a deserted look. These are huge paved spaces with no shade and serve as a perfect reminder of how an inappropriate climatic design, choice of materials and forms can render a public space useless. Photo: Sugeet Grover
The recently constructed urban space in Lucknow bears a deserted look. These are huge paved spaces with no shade and serve as a perfect reminder of how an inappropriate climatic design, choice of materials and forms can render a public space useless. Photo: Sugeet Grover The recently constructed urban space in Lucknow bears a deserted look. These are huge paved spaces with no shade and serve as a perfect reminder of how an inappropriate climatic design, choice of materials and forms can render a public space useless. Photo: Sugeet Grover

The world faced severe heatwave this year. The mercury in France touched 45.9 degrees Celsius, which is nearly two degrees above the previous record. In the face of this onslaught by the weather gods, a pertinent question arises: How should our built stock respond to this?

Nature provides us with our best defense. Our skin provides us with the first layer of covering that protects the vital components of the body.

The second layer is the one, which we are able to manipulate to our advantage according to the weather conditions. One prefers a more breathable fabric in sweltering heat, while a thicker fabric is favoured in the winter seasons, when it’s important to conserve body heat.

The third layer is the design of the building envelope. This layer can be intelligently designed by using the correct orientation, proper shading devices and perhaps most importantly, the appropriate building material.

Despite these three layers, thermal comfort remains elusive making us rely on active technologies for our cooling needs.

India is set to be among countries, which would lose productivity due to heat stress that will arise due to the effects of climate change, according to a recent study by the International Labour Organization.  

The loss in productivity is worse in countries like India owing to the sheer size of its population and its dependence on outdoor physical jobs related to construction and agriculture. The loss is estimated to be equivalent to 34 million full-time jobs.

Urban heat island effect 

Global warming is not the only reason behind the rise in ambient temperature. Our ever-expanding urbanisation (urban sprawl) is also responsible.

The ever-increasing built mass, combined with a destruction of trees inside urban areas, has led to a phenomenon called the urban heat island effect. This occurs as the high density of buildings absorbs heat and traps it, thus increasing the ambient temperatures in the dense urban areas in comparison to their rural counterparts where built density is lesser.

How significant is this rise in temperature?

The urban heat island effect was responsible for a temperature rise of up to 3.7°C during pre-dawn time in Kochi, according to a study.

This temperature can make the difference of an air-conditioner being switched on or off remain off during certain months of the year, having a huge impact on energy consumption.

Every extra degree centigrade of temperature that the AC takes to cool is responsible for a 6 per cent increase in electricity consumption, according to the Bureau of Energy Efficiency.

The third layer, thus, has to deal with an increasingly hostile ambient temperature. Can this ambient temperature be worked upon? The answer is easily observable.

Traditional architecture 

Open public spaces would have local pocket of areas that feel more comfortable than the others — a space with sunshine would be preferred in winters, while a cluster of trees is heavily sought after when the sun is blaring down. A water fountain or water body can add that extra element of moisture on a hot and dry day to bring relief.

Shade, sun, surface and moisture all play a part in making an open space usable. The appropriate combination of these elements is dependent on local climate conditions and the context they are in.

The central courtyard of the India Habitat Centre in New Delhi is one such example of how microclimate of an open sky space has been played upon. The space frame is designed in a way that blocks the overhead sun. A portion of the courtyard is in itself shaded by the building blocks. The trees apart from providing shade also contribute to the moisture because of evapo-transportation.

The effects of shading devices, building courtyard and trees gets combined with the cooling effect of the water bodies and the resulting effect is a noticeable change in the comfort level when one walks in into the courtyards.

Our traditional architecture gives us examples of such interplay; the narrow streets of cities in Rajasthan were built in a way that the buildings shaded not just the street below but also the building in front, giving respite even to the passersby.

The current mass housing construction, however, seems to have forgotten these. Most housing projects in Delhi-NCR have Dubai-esque towers galore. This typology is in contrast from the traditional urban forms of the city, which had smaller shaded spaces, were more useful and also required lesser maintenance as compared to the sprawling unshaded lawns.

In current housing projects, trees are grown over a basement and hence cannot go much deep. It ends up being more ornamental in nature, hampering their growth and also jeopardising their potential for providing shade.

The lack of comfort in open spaces will turn away people from using them thus dissuading sociability of the space; this could become an even more significant issue as the ambient temperature rises. For example: The spaces around the Fatehsagar Lake had lower footfall because of the excessive heatwave, reported the Udaipur times.

The careful design and planning of urban forms, greenery and water bodies provides us with a potential to change the microclimatic conditions of open spaces. These efforts need to begin on a particular site and then expanded to the city.

In our fight against climate change and a bleak scenario where every building would be air conditioned and open spaces would be abandoned, let us give an­ alternative future a fighting chance.

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