New technology could turn wasted heat energy into electricity

Australian scientists say a new technology could harvest waste heat from power stations and vehicle exhaust pipes to generate electricity. Monash University researchers report they've developed an ionic liquid-based thermocell with high power outputs and no carbon emissions. Thermocells work by harnessing the thermal energy created by the difference in temperature between two surfaces -- one warmer and one cooler -- and converting by means of an electrolyte into electrical energy. The new thermocell could be used to generate electricity from low-grade steam in coal fired power stations at temperatures around 266 degrees Fahrenheit, Monash scientists say. "We have found that it can work at elevated temperatures typical of important heat sources, as opposed to water-based systems, which cannot operate at temperatures above 100 degrees Celsius (212 degrees F., the boiling point of water,)" researcher Doug MacFaralane said. "The device offers the possibility of a cheap and flexible design suitable for harvesting waste heat in the 100- to 200-degrees Celsius range," he said. The thermocell is an attractive method of relieving some of the present reliance on fossil fuels, Monash doctoral student Theodore Abraham said, because it uses heat already produced in industrial processes that would otherwise be untapped. "The major benefit of a thermocell is that it harnesses energy that is already readily out there; you're just harnessing energy that is otherwise lost to surroundings," he said.