II-VI Marlow Blog

Energy Harvesting in the Dark

This entry was posted in Energy Harvesting , Thermoelectrics , renewable energy and industries on January 06, 2020 by II-VI Marlow Industries

energy harvesting

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:

  1. Generating light from dark IS possible and has the potential to be scalable at large
  2. This type of energy can be extremely cost effective - Raman’s prototype cost $30
  3. There is an opportunity for clean, low-cost energy solution in developing countries

As this energy harvesting method grows, scientists will be challenged with keeping costs low. Researchers suggest this type of energy can be used to power carbon free-lights or sensors in remote locations. However, materials will need to produce a much greater output to supply homes and villages with the appropriate amount of energy.

With such promising capabilities, you can expect to hear more about this exciting, transformative energy in the future!

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