Researchers from the Ohio State University invented a material that could be used in the automobile industry to recover the heat lost through the cars’ exhaust systems. The same technology could work in power generators and heat pumps, said project leader Joseph Heremans, Eminent Scholar in Nanotechnology at OSU.
Mechanical experts say that only 25% of the energy produced by burning the fuel is actually used in a normal gasoline car, the rest being lost through heat. There already are some products on the market that do the same job in recollecting the lost heat and transform it to electricity, but they only have an efficiency of roughly 0.71%, while the new invented material has 1.5%.
The Thermoelectric (TE) device they invented works best in the interval of 450 and 950 degrees Fahrenheit (232 to 510 degrees Celsius), range of heat that applies best to an automobile’s engine. The TE does it all by itself, transforming the heat directly into electricity.
Heremans says: “The material does all the work. It produces electrical power just like conventional heat engines – steam engines, gas or diesel engines – that are coupled to electrical generators, but it uses electrons as the working fluids instead of water or gases, and makes electricity directly.”
“Thermoelectrics are also very small,” he adds. “I like to say that TE converters compare to other heat engines like the transistor compares to the vacuum tube.”
Normally, the TE material’s development would suppose reducing the thermoconductivity of the material to capture most of its heat energy, but the OSU researchers took another path. They didn’t use nanostructures, which are very hard to make, to connect to electrical circuits, and to maneouver, but used some properties of tellurium and thallium.
“We hope to go much further. I think it should be quite possible to apply other lessons learned from thermoelectric nanotechnology to boost the rating by another factor of two — that’s what we’re shooting for now,” he said.