We’re all familiar with solar panels. How they absorb light that can power just about anything. But what if we told you energy can now be harvested in the dark.
UCLA scientist, Dr. Aaswath Raman, explored this idea of turning darkness to light after traveling through a village in Sierra Leone with no access to power at night. He hypothesized that coupling cool, dark air from space and natural heat flowing under a platform could generate enough energy to power a light bulb.
This theory is supported by the radiative cooling principle - objects radiate heat absorbed during the day into space at night. Radiative cooling also explains why you may see morning frost on the ground. The temperature difference between the exposed surface and the air beneath creates electricity.
Raman collaborated with scientists from Stanford University to test his theory using this principle. Together they created a thermoelectric generator comprised of styrofoam wrapped in aluminum, a metal disc painted black, a voltage convertor, and an LED light bulb. They placed the homemade model on a roof and monitored its electrical output for 6 hours. Not only did it power the light bulb, it generated 25 mW/m2.
While this experiment was minimal impact, it demonstrated three important things: