thermovoltaicsA less known member of the solar-cell family is the thermo-photovoltaic cell. Nevertheless this piece of technology can be very useful for industries and for households to save on their electricity bill.

ThermoPV cells generate electricity from photons that are emitted by a nearby heat source instead of the sun. You can’t use just any heat source though; it must be at 1000°C or more, and emit a lot of radiative heat. This is the case for glass or steel ovens, high-temperature combustion furnaces, or burners in domestic heating systems producing warm water. I agree that this is not as big a market as the solar cell market, but why not use the heat that is produced anyway in a useful way. We purify waste water to be able to reuse it because water is a scarce source. Electricity is also expensive and scarce, so let us use every energy source that is available.

Up till recently, thermoPV cells were rather expensive. Researchers have now come up with a way to make them more affordable and therefore more realistic to use in daily life. The trick is to use a low-cost process flow which is industry applicable. Also, they use (germanium) substrates with relaxed surface finishing conditions, giving comparable performance as cells made on substrates with a polished surface.

Imagine in a few years from now that you have in your home a heating system that provides its own electricity. The integrated thermoPV cells which first seemed like a luxury asset in the folders of your heating system supplier, now harvest the waste heat and make the heater into an autonomous appliance. The combustion furnaces which you see on your drive home even generate an excess of electricity that they can feed back to the electricity grid. They produce green electricity by treating your waste.

Never thought that waste could be a good thing.