A new wrinkle on an old technology — solid-state thermophotovoltaics (TPV) — could provide a high-efficiency alternative for directly converting high-temperature heat from concentrated solar thermal to utility-scale electricity.
Researchers are developing a thermal storage system that uses liquid tin as a transport fluid. The technology could help increase the efficiency of energy systems based on concentrated solar thermal energy.
New computer modeling suggests that high-temperature TPV conversion — which captures infrared radiation from very hot surfaces — could one day rival combined-cycle turbine systems when used with liquid metal thermal storage at temperatures around 1,300 degrees Celsius. Advances in high-temperature components and improved system modeling, combined with the potential for conversion costs an order of magnitude lower than those of turbines, suggest that TPV could offer a pathway for efficiently storing and producing electrical power from solar thermal sources, a new study says.
“The goal for our study was to provide a heat transfer and thermodynamic perspective on a system that combines concentrated solar power with thermal storage and TPV to show that such a system is worthy of renewed attention,” said Asegun Henry, an assistant professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech. “In the context of the full system, we suggest that the efficiency could one day rival the best heat engines available on the planet today.”
The underlying technologies of high-temperature storage and TPV conversion could also be used to produce grid-scale batteries able to rapidly supplement other power sources by storing heat for quick conversion to electricity. TPV operates on the same principle as solar cells in wide use today but converts photons at infrared wavelengths rather than those in the visible spectrum.
The modeling was done by graduate research assistant Hamid Reza Seyf in Henry’s lab. Supported by ARPA-E, the research was reported in the journal Energy and Environmental Science. — John Toon