In an effort to find a clean alternative to air conditioners (ACs), two students from The Indian Institute of Technology (IIT) Kharagpur have come up with an innovative cooling system that would cut up to 50% of cooling costs. ACs require a huge amount of energy to run; they account for 40% of Delhi’s total electricity and 20% of total household electricity in the US. With the waves of heat surging in, especially in regions close to the equator, AC consumption in turn skyrockets. In India, ACs contribute to about 35% of total household electricity consumption and produces 1.5 tons of carbon every year.

Sahashranshu Maurya and Somrup Chakraborty from the Department of Geology and Geophysics designed a passive solar water wall that serves a cooling system, and entered it into the Shell Ideas360’s audience choice awards and were placed in the five finalists.

Their cooling system is composed of a water tank inserted into walls. Maurya finds their innovation has strong ties to the concept of future cities, explaining that the water tank is different from conventional tanks as it has a very high surface area so maximum air can interact with the tank walls and get cooled. The water absorbs the heat and passively circulates, keeping the inner wall relatively cool, reducing the air temperature and the need for ACs.

“For a basic set up, an initial investment would be about a lakh of rupees (100,000 rupees, around $1,500). The design would evolve depending on the architecture,” he said during his pitch in the Shell Ideas360’s audience choice awards. “A large number of ACs contribute to the increase in local urban temperatures. The efficiency of the ACs depend upon the temperature difference they are trying to maintain. They are creating the very problem they are trying to solve. Also consider the scenario that the global average temperature is increasing. The number of ACs in the market is going to sore. Is that the real solution?”

The team, Taknique, argue that their cooling system creates no chlorofluorocarbon emissions, no carbon emissions and almost negligible electricity usage. Water has a high heat capacity, so it resists any major temperature change by absorbing heat. If Taknique installs their water tanks in the walls of the buildings, they say they can make them resistant to major temperature changes; in addition to that, the heat absorbed will be continuously removed from the system by daily household use of water.

The other four in the finalist round of Shell Ideas360’s audience choice awards came from Europe, U.S.A. and Asia. Students at Cambridge explored if 3D printing could purify water, while those at Delft experimented to see if they could actually make use of plastic bottles found in sea while keeping them there. Students at Nanyang explored if there are storage solutions in soil and others in Austin explored the possibility of creating more intelligent solar panels that by shaping memory alloy into springs that stretch when cool, producing a solar panel that always faces the sun’s position in the sky by responding to a temperature gradient.