102. Solar Panels Generate Power at Night, Rocket Catching Helicopter, Robotic AI Beekeeper Startup

NEWS <p> </p> <p><a href='https://interestingengineering.com/stanford-solar-panel-night'>Stanford engineers invent a solar panel that generates electricity at night</a> | Interesting Engineer (01:08)</p> <ul><li style="font-weight:400;">Solar panels at night can freely radiate infrared light out into space.<ul><li style="font-weight:400;">Solar panels — like everything warmer than absolute zero — emit infrared radiation. </li> <li style="font-weight:400;">Cloudless nights being optimal, because no clouds equals less reflection of the infrared light onto the ground.<ul><li style="font-weight:400;">Radiative cooling (surface is cooler than air) phenomenon that only happens when skies are clear. </li> </ul> </li> </ul> </li> <li style="font-weight:400;">That flow of energy enables the device Stanford University researchers created — an ordinary solar panel outfitted with a thermoelectric generator — to generate a small amount of electricity from the slight difference in temperature between the ambient air and the surface of a solar panel pointed deep into space. </li> <li style="font-weight:400;">Lead researcher,  Sid Assawaworrarit, states:<ul><li style="font-weight:400;">“There’s actually light going out [from the solar panel], and we use that to generate electricity at night. The photons going out into the night sky actually cool down the solar cell.”</li> </ul> </li> <li style="font-weight:400;">Photons leave the sky facing surface of the solar panel, and they carry heat with them. <ul><li style="font-weight:400;">The surface of a solar panel will be a few degrees cooler than the air around it. </li> <li style="font-weight:400;">A device called a thermoelectric generator can capture some of the heat flowing from the warmer air to the cooler solar panel and convert it into electricity.</li> </ul> </li> <li style="font-weight:400;">On a clear night, the device tested on the Stanford rooftop generates roughly fifty milliwatts for every square meter of solar panel (50 mW/m2). <ul><li style="font-weight:400;">They be