Do you feel the warmth coming off your computer or cell phone? That’s wasted energy radiating from the device. With automobiles, it is estimated that 60% of fuel efficiency is lost due to waste heat. Is it possible to capture this energy and convert it into electricity?
Researchers working in the area of thermoelectric power generation say absolutely. But whether it can be done cost-effectively remains a question.
For now, thermoelectric generators are a rarity, used primarily in niche applications like space probes, where refueling is not a possibility. Thermoelectricity is an active area of research, particularly among automobile companies like BMW and Audi. However, to date, the cost of converting heat to electricity has proven to be more expensive than the electricity itself.
Anveeksh Koneru, a senior lecturer in mechanical engineering at The University of Texas Permian Basin, is exploring a new method for capturing waste heat by harnessing the quantum mechanical motions of electrons in spin polarized materials.
Koneru believes that he may have found the right material to harness the effect for energy production – cobalt oxide. The material is traditionally used in the ceramic industry to create blue colored glazes.
"The material should be a good electrical conductor, but a bad thermal conductor. It should conduct electrons, but not phonons, which are heat," Koneru said. "To study this experimentally, we’d have to fabricate thousands of different combinations of materials. Instead, we’re trying to theoretically calculate what the optimal configuration of the material using substitutions is."
Koneru has been using supercomputers at the Texas Advanced Computing Center (TACC) to virtually test the energy profiles of a variety of cobalt oxides with a range of substitutions.
"Each calibration takes 30 to 40 hours of computing time, and we have to study at least a 1,000 to 1,500 different configurations," he said. "It requires a huge computational facility and that’s what TACC provides."
Once he identifies the optimal material for waste heat conversion, Koneru hopes to engineer a paste that could be applied to the tailpipe of a vehicle, converting waste heat into electricity to power a car’s electrical systems. He estimates that such a device could cost less than $500 per vehicle and could reduce greenhouse gas emissions by hundreds of millions of tons annually.
"With the recent advances in nanofabrication, and computational calibrations for nanomaterials, spin-thermal materials can play a vital role in energy conversion in the future," he said.
