Thermoelectric Heating Comes in From the Cold
11th December 2024
A decade ago, thermoelectric heating—which relies on the thermoelectric effect, in which electrons are pulled from one material to an adjacent material when both are heated—still required toxic or rare materials such as lead and tellurium. Because the thermoelectric effect is reversible, it also opens the door to cooling, with none of the environmental impact of using liquid refrigerants, or requiring industrial waste heat to be recovered as electricity.
However, the thermoelectric effect is so small in most materials and for small temperature differences that its real-world use so far has been mostly in space vehicles and for precisely controlling the temperature of donated organs for transplant. Researchers use a dimensionless quantity called ZT to describe the strength of the thermoelectric effect in any combination of materials. Two decades ago, combinations such as lead and tellurium yielded ZT values of around 1. After ten years, the search for new, more complex, and more effective materials had yielded ZT values of 2. In 2009, thermoelectrics researcher Cronin Vining wrote in Nature Materials that “commercial quantities of materials and/or efficient devices…does not seem imminent.”
But since then, materials scientists have been reporting more and more materials, such as tin selenide, and half a dozen other combinations, that lend themselves well to the thermoelectric effect.