04/21/2005: 
Technologica
A/C Powered By Car Exhaust?
from ABC
A South Australian researcher is harnessing heat from car exhausts to run a cheaper and more environmentally-friendly air-conditioning system for cars.
The average car engine only uses less than half the heat energy generated by fuel combustion.
Adelaide PhD student Luke Zoontjens is using waste heat in car exhausts to generate high-amplitude sound waves that can power a car's air-conditioning.
"Even at conversation levels, you have very small changes in temperature, and they're of the order of about a thousandth of a degree," he said.
"What we're doing here is we use very high sound levels where the temperature changes are much higher."
Sound waves resonating inside sealed metal tubes create cold spots.
Blowing air over these spots then cools the inside of the car.
Mr Zoontjens says successful application of this technology will reduce fuel usage, environmental pollution, and costs associated with car-cooling systems.
