With fossil fuels depleting every day, humanity has embarked on a quest to find clean sources of renewable energy. And whatever we have come across, has some caveat or another. Take solar energy for example. Solar energy only works best in locations with ample sunlight and cool temperatures.
But, it is not possible to generate solar energy during night time. However, scientists have now developed a new tech that could actually allow you to do just that.
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Engineers at UCLA and Stanford University have created a technology that generates electricity out of cold air that flows in the night. First published in Joule, the technology is based on 'thermoelectric generators' that generates electricity when heat passively moves from a warm place to a cold place.?
They have put together a device that produces a voltage by directing the day's residual warmth into cooling air.
They make the use of a material called a thermocouple, which allows the engineers to convert a change in temperature into a difference in voltage. For this to work, one needs something really warm on one end and an outlet for the heat to escape on the other.
To make this work, they used some really cost-effective materials that are easily available in hardware stores near us. They created a thermoelectric generator and paired it with a black aluminium disk to release heat in the air during nighttime (it was placed upwards, facing the sky). The generator was kept inside a polystyrene box with a transparent window, and connected to a single LED light. All this cost less than $30 or Rs 2,100.
Aaswath Raman
It was placed on the rooftop of a chilly Standford night (where the temperatures dropped freezing temperatures) which was able to light the tiny LED to life.?
Now, this technology as of now isn't the most powerful, as a square metre of such units could only generate 25 milliwatts. Right now it can power an LED light or charge your smartphone, really slowly. While this is really less electricity, a few tweaks could make it deliver more yield.?
According to Aaswath Raman, Assistant Professor for Materials Science and Engineering at UCLA, "We think this forms the basis of complementary technology to solar. While the power output will always be substantially lower, it can operate at hours when solar cells cannot. Beyond lighting, we believe this could be a broadly enabling approach to power generation suitable for remote locations, and anywhere where power generation at night is needed."