Exhaust-to-energy technology to bolster fuel efficiency

Scientists say that cars will be able to save up to 10 per cent of their fuel within ten years by converting waste energy from their exhausts into electricity.

BSST, a participant in the Department of Energy’s Freedom Car initiative, is developing a component designed to fit to a car exhaust that is capable of converting waste heat into usable energy. Lon Bell, president of the company, said that a typical installation could harvest a kilowatt of energy in a passenger vehicle.

The company has been selling the Climate Control Seat, a seat designed to apply either heat or cool air directly to a passenger’s body using electrically-powered heat exchange materials. "We want to reverse the process, using the exhaust system to harvest the waste heat and convert as much as possible to electric power,” explained Bell, predicting demonstration units would be completed next year, and commercialisation of the product would be achieved four to six years after that.

Hybrid and plug-in hybrid cars produce less heat when using their electric drives, which makes the system less suitable the larger the electric battery used to drive a vehicle becomes, admitted Bell.

However, he hopes that the technology will scale for use in the truck industry, which has been struggling to cope with high oil prices.

"In heavier vehicles, people are also looking at electro-turbo-compounding, which uses waste heat energy to spin a turbine to produce power," said Bill Van Amburg, senior vice president at Californian alternative transport research centre WestStart-Calstart.

Interest in heat-to-electricity systems is growing. US start up Eneco is developing a solid state chip that can convert heat into electricity, while GMZ Energy is also developing its own materials for exhaust heat capture.