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Cake day: December 14th, 2023

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  • Solar panels collect solar energy and turn it into electrical energy. Radiative cooling takes heat and sends it into space via Infrared. This is pretty simple as all matter above 0K loses heat energy by emitting IR. While it is slightly more effective at night, it works all the time if you set it up right (in other words shade it so it doesn’t absorb more heat via the sun.

    Ancient civilizations like the Babylonians used this concept to make ice in the desert. If you build a tall enough tower you can put a pool of water in eternal shade but always being able to emit IR into space. Add some well placed vents and you lose more heat via evaporative cooling.

    With billions more people starting to have access to modern technologies and wanting/needing air conditioning to survive we must utilize these ideas to manage power consumption without killing the planet even more.

    A grocery store near LA did an experiment where half of it’s roof was solar and half was radiative cooling its fridges and the radiative cooling was more effective and more consistent. Cloudy sky means no solar but radiation is still leaving your building, it’s just warming the clouds instead of space.

    If you have a black roof it absorbs light and your house warms. If you have a white roof it reflects light meaning less heat. If you can reflect IR even better. Most of the ways we make white paint for hard surfaces is by suspending tiny bubbles in the paint. More bubbles more reflections including IR. With enough layers of white paint you can get a roof cooler then ambient air.