Interview with Vivek Gilani

The cardboard on the hot tin roof

Magazine 94 – Spring 2022

With his company cBalance, environmental engineer Vivek Gilani advises Indian companies, authorities and citizens on how they can protect the climate. The FairConditioning program he founded has – among other things – a focus on sustainable and affordable cooling solutions for people in slums.

Vivek Gilani
Vivek Gilani, cBalance
They work in Indian cities like Pune and Bangalore. What effects does heat have on the people you advise?

Gilani: Many people we work with in Pune live in houses with tin roofs and walls. These have no windows, but the next building is usually directly opposite, which makes ventilation difficult. Only recently we again measured more than 40 degrees room temperature in such houses, and then it was not even summer. Buildings in Bangalore often have very low ceilings, which also creates a warmer indoor climate and creates ventilation problems. The residents tell us about complaints such as headaches, nausea, dizziness, skin swelling and shortness of breath. Their sleep cycles are disrupted and there are days when they don't fall asleep until XNUMXam, making them irritable during the day. Children suffer from sleeping and learning problems, older people from loss of appetite. Cooking in overheated rooms is also difficult and food spoils easily. 

How do people try to cope with the heat? 

Gilani: Many things are being tried to counteract the heat stress: they pour water on their roofs or cover them with cardboard so that the sheet metal does not heat up. Some build roofs out of coconut leaves to keep the interior cool. They mop floors for a cooling effect and often bathe in cold water. Many also sleep directly on the floor and sit in front of their houses during the day and wait until the inside temperatures become bearable. Some residents own fans with evaporative coolers.

cBalance roof window
Better ventilation through a dormer window
Which of the cost-effective cooling solutions recommended by cBalance have proven particularly effective?

Gilani: Aluminum foil and similar materials, which can also be obtained from waste, can be very effective as radiation barriers on roofs. This allows interior temperatures to be reduced by five to six degrees. In pilot programs in informal settlements, we therefore rely on such aluminum foil barriers. In windowless homes, we also install small skylights to help with ventilation. In hot and dry regions, such passive cooling solutions should be combined with inexpensive evaporative coolers. In tropical, humid places like Mumbai or Chennai, however, we also need dehumidification, which is usually possible with compressor cooling like with an air conditioner. But there is also an eco-friendly alternative suitable for informal settlements, namely well-designed and insulated ice box air conditioners. They don't cool the whole house, but they make the heat more bearable for the residents. Such air coolers can be operated using a small photovoltaic panel, a fan and ice blocks.

The foil serves as a barrier to radiant heat during the day. At night it can be pushed back to allow the heat trapped in the house to escape better.
Is the problem mainly one of making known solutions accessible? Or do you also need innovations? 

Gilani: There are numerous cooling solutions. However, these must be better adapted to the social, ecological, economic and climatic context. Specifically, evaporative cooling systems could be coupled with rainwater tanks. This means that people in arid areas can also use these cooling systems. Or, to take the example of ice box refrigeration: Here it would be important for the ice to be produced locally, sustainably and inexpensively. For example, from ice cream producers who work with solar vapor absorption machines and who use natural, more climate-friendly refrigerants such as ammonia.

Many thanks for the interview!

You can find more information about Vivek Gilani's consulting firm here: cBalance