Listen: Heat Loss to Night Sky Powers Off-Grid Lights
"This is scientific American sixty seconds science. I'm Suzanne barred switching on the lights at night. It's second nature feature to most people in the developed world but electricity isn't too given in many other parts of the globe something like a billion people on our planet still lack reliable access autrocities think about folks in parts of the developing world that are living in off grid locations and for them. One of the central applications of Electricity Chrissy is lighting and we need lighting the most at night. UCLA MATERIALS SCIENTISTS OSHAWA thrombin solar cells can provide remote wrote areas with electricity during the day but require batteries to store that energy for use at night. Rahman's team has developed a potential solution a simple pull thermoelectric device that generates power when it's exposed to the cool night sky it's made possible by phenomenon called Radiative Sky Cooling Rolling all objects Rahman explains radiate heat and so what that means from the perspective of service. That's looking up at the night. Sky Is Ebel all by itself set out more heat than the sky sends back to it that escapes to the upper atmosphere and even out to outer space and is something that anyone can observe observe at night so if you go and measure the roof temperature on your house in the early morning hours say you should read temperature that is much lower. Dante immediate ambient air temperature Roman reason that this temperature difference could be exploited to generate electricity. His team built their device using an aluminum luminous disk that acts is a radiative cooler. It's cool side faces. The night sky while it's other side is warmed by the air around it. As heat escapes apes upwards a thermoelectric generator converts the temperature difference into electricity that powers a small led light for now. The energy output of the device device is just a tiny fraction of a solar cell can produce but engineering improvements could eventually boost its performance. Rahman sees the devices a compliment to solar providing inexpensive twenty four hour power generation to remote areas of the world without the need for batteries. You can also think about say the polar regions where for several months of the year there is no sun at all so in those kinds of regions this might represent one of the few ways you can actually generate power naturally at night. The research is described in the journal jewel in addition to lighting. Rahman says the device could be useful for specialized applications such as powering wireless sensors and monitoring atmospheric conditions or it could be a really cool way to recharge your cell phone at night. Thanks for listening for scientific Americans sixty seconds science. I'm Suzanne Bard."