Powering LEDs With Candles

Here’s a novel lab experiment, courtesy of Tetsuo Nozawa at Nikkei Electronics: it’s an LED powered by candle flame. Check out the photo at the above link.

The heat from the candle goes through a thermoelectric material and is converted to electricity, which powers the LED. Nozawa saw it at Nextreme Thermal Solutions. The LED actually shines brighter than the candle flame because most of the energy in the candle is dissipated as heat. In LEDs, most of the energy gets consumed in producing light.

Thermoelectric materials like bismuth telluride have been studied for decades. Researchers, however, have begun to experiment with different types of materials (such as germanium) that they say can convert heat to light and vice versa much more efficiently. Companies trolling in thermoelectrics include GMZ Energy, Promethean Power, and Cypress Semiconductor. UC Berkeley is concocting some startups too.

Although thermoelectric materials technically exploit waste heat, most of the waste heat companies that have been in the market for years use very different underlying technologies. These companies typically capture heat, compress it, and then use the resulting pressure to run a turbine and create electricity. Alternatively, they pipe the heat back into the factory to warm water or offices.