March 11, 2009
School of Engineering, Amritapuri
Second year mechanical engineering students from Amritapuri recently won the first prize at a tech fest organized at NIT Trichy for their innovative design to cool water without using electricity. They won the top prize after beating teams from over 50 engineering colleges that also participated in the contest. While other teams used expensive materials like liquid nitrogen (a cryogenic fluid) or CaCl2 (a chemical which a produces a cooling effect), the Amrita students built a low-cost evaporative cooling tower that used no chemicals, no CFCs, yet produced an appreciable cooling effect.
"The inspiration for our model came from studying natural processes of cooling," shared Praveen R, one of the three students on the winning team. "For example, the human body produces a cooling effect through evaporation of sweat. This same principle also cools water in an earthen pot. We used this in our evaporative cooling tower and we tried to increase the rate of evaporation to the maximum. This was achieved quite fortuitously when we used mosquito nets in the tower. The nets helped increase the surface area of contact, thereby increasing the efficiency and the rate of evaporation."
Mosquito nets in a tower? The tower was actually made of three buckets, inverted one on top of another; in between were the nets. The students purchased a mechanical blower for Rs. 200, the only piece of equipment that they had to spend some money on. This was used to blow air from the bottom as water was sprayed from above. Water drops collected on the mosquito nets. As these drops partially evaporated when the air passed through them, cooler drops collected in a jar placed at the bottom of tower. In five minutes, water temperature dropped by six degrees.
"We are proud of our students," stated Mr. Mohan CC of the Department of Mechanical Engineering, who provided guidance to the student team and helped them make a working model. "The technique demonstrated by the students is cost-effective and non-polluting. It is suitable for the air conditioning and refrigeration industries also, which rely on the use of CFCs that greatly contribute to global warming." Abhijith Vijayan and Sreerag S.R., the two other members of the winning team agreed. "We won a prestigious cash prize of Rs. 7000/-. But we will be really happy only when we begin to see commercial application of this idea."
We congratulate the winning team and hope that their innovative design finds widespread adoption and use.