Thermoelectric Heating Comes In From the Cold

Thermoelectric Heating Comes In From the Cold

Before architect César Martín-Gómez could send his latest thermoelectric experiment to Antarctica in 2018, he had to make sure that soldiers from the Spanish Army could get it right on the first try. In the laboratory, he could always run the experiment—a scale model of a solid-state thermoelectric heater—a second time if it needed troubleshooting.

But at Spain’s Gabriel de Castilla base in the South Shetland Islands, soldiers would be too busy running other civilian experiments to troubleshoot Martín-Gómez’s for him if it failed. And in a place like Antarctica, the goal of his experiment—providing efficient heat from direct current electricity—was both important and difficult. The experience “forced us to make a jump in quality,” recalls Martín-Gómez, who is a professor at the University of Navarra in Pamplona, Spain.

That jump is part of a broader maturation of thermoelectric heating, and the demand for climate-friendly climate control technology is starting to grow. In September, the U.S. Climate Alliance, representing half the states in the United States, pledged to quadruple the number of heat pumps in the country by 2030. In November, the U.S. Department of Energy offered US $169 million in funding to help heat pump manufacturers expand. Heat pumps are one way forward, but thermoelectrics may represent a simpler next generation of climate control technology.

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.

“The thermoelectric cell just goes in the facade and liberates the rest of the building, which architects love.” —César Martín-Gómez, University of Navarra

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. While some…

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The post “Thermoelectric Heating Comes In From the Cold” by Lucas Laursen was published on 12/05/2023 by