Researchers at MIT and Stanford University have found a way to convert waste heat into electricity at temperature differences of less than 100°C. Their approach, based on the thermogalvanic effect, is described in a paper published in the journal Nature Communications. The paper's authors include postdoc student Yuan Yang and professor Gang Chen at MIT and postdoc student Seok Woo Lee and professor Yi Cui at Stanford.
Their approach involves using waste heat to heat a discharged battery. The battery is then charged at the higher temperature and allowed to cool before use. Energy from the waste heat applied to the battery can then be recovered during discharge.
A demonstration showed that a temperature differential of 60°C allowed for an estimated efficiency of 5.7%.
According to MIT News, Chen said the basic technique was proposed in the 1950s but required temperature differentials of 500°C or more.
David L. Chandler of the MIT News Office quoted MIT's Yang as saying, “One-third of all energy consumption in the United States ends up as low-grade heat.”
Visit MIT News for more information.