Friday, November 5, 2010

Heat scavengers come in from the cold

The vast quantities of heat lost each day – whether from car engines, power-plant chimneys or simply sunlight – is a largely untapped source of energy that could be used to make electricity or simply warm our homes. Decades of research show that it's tricky to capture and use such heat cost-effectively, but a spate of new studies suggest some solutions. Thermoelectric materials, which convert a temperature difference across their surface into a current, offer yet another way to generate energy from waste heat. Most existing thermoelectric devices are based on rare, expensive and unstable materials such as bismuth telluride, making them unsuitable for widespread use in energy generation – but Peidong Yang of Berkeley Lab has found a cheap alternative in silicon. More>