The BIT-Sindri team with the thermoacoustic chamber, which uses high-amplitude sound waves to control temperatures, on campus on Thursday. (Gautam Dey)

Did you ever think that blaring horns of vehicles can be put to good use? If not, check out this cool innovation from the BIT-Sindri stable.

A bunch of six mechanical engineering students of the state-run tech cradle have invented a thermoacoustic device that uses high-amplitude sound waves to lower atmospheric temperatures.

The low-cost cooling unit , developed over the past four months, was unveiled during their final semester viva voce on Thursday.

Ratikant Upadhyay, Rajnikant Singh, Piyush Ujjaval, Sanoj Kumar Soren, Sanjeev Tirkey and Vikash Kumar completed the project under the guidance of professor J.N. Mahto. Head of the mechanical department S.C. Roy supervised it.

Developed at a cost of just Rs 6,000, the thermoacoustic device can drag down temperatures by around 20 degrees in a matter of 10 minutes. But, what makes the appliance even more unique is that unlike our refrigerators — where ammonia or chlorofluorocarbon gas is used to control the cooling mechanism — this apparatus is eco-friendly because there is no use of ozone-depleting or toxic coolant.

“The equipment works on expansion and compression of sound waves,” said Ratikant who is also group leader.

Explaining the model further, he said that during compression near the nodes of a wave, heat is absorbed from the atmosphere while near antinodes heat is released. “We created the cubical chamber where sound is produced through a speaker. After properly calculating the frequency of the waves, the length of the nodes were determined,” Ratikant explained.

He added that a heat absorber — made of camera rolls — had been installed near the nodes and it helped in quickly lowering temperatures.

“If instead of air had we used Helium, our performance would have been 200 times better. But, the cost would have escalated,” Ratikant said, adding that the cost of making the device was shared among the six of them.

The final-year student also expressed his dream to build a thermoacoustic refrigerator that would be able to lower the temperature to 0°C.

Department head Roy lauded the efforts of his students. “Team work coupled with professor Mahto’s guidance yielded the amazing result,” he said.