Heat recovery device can boost efficiency of solar energy systems

Wasted heat is a problem in many industrial sectors. For some, generating heat costs money, and if it’s allowed to leak out of systems then that impacts on profitability. For other sectors, it's simply a lost opportunity. In solar energy, for example, heat lost to the environment is energy that has not been converted into electricity – the sole purpose of the equipment.

Engineers at Rice University in Texas have used the results of some previous research into producing close-packed arrays of precisely aligned carbon nanotubes to address this issue. In a paper in the journal ACS Photonics, they describe how such arrays have the potential to boost the efficiency of photovoltaic panels from around 22 per cent to a theoretical maximum of 80 per cent.

A group of researchers led by Junichiro Koro of the Brown School of Engineering at Rice discovered a simple method to create such nanotube arrays on the scale of a semiconductor wafer in 2016. Koro then recruited a newcomer to Rice, Gururaj Naik, to work on a project to see whether this discovery could be put to use to direct thermal photons. "Thermal photons are just photons emitted from a hot body," Kono said. "If you look at something hot with an infrared camera, you see it glow. The camera is capturing these thermally excited photons."