Cryo-Paint: Passive Radiative Cooling for Sub-Ambient Temperature Control
Generated: 2026-06-08 · API: Gemini 2.5 Flash · Modes: Summary
Cryo-Paint: Passive Radiative Cooling for Sub-Ambient Temperature Control
Clip title: I Made The World’s First Self-Cooling Clothes Author / channel: The Action Lab URL: https://www.youtube.com/watch?v=FnKNOPlR2Yo
Summary
The video explores the innovative concept of “cryo-paint,” a specialized coating designed to cool objects below ambient air temperature, even when exposed to direct sunlight, without requiring any energy input. The presenter first demonstrates this by painting a metal panel and showing that its temperature in direct sunlight is 83°F, surprisingly cooler than the 85°F measured in the shade. This effect is starkly contrasted with a standard white panel, which reached 117°F, and a black panel, which soared to 175°F under the same conditions.
The scientific principle behind this remarkable cooling lies in three forms of heat transfer: conduction, convection, and radiation. The key to the cryo-paint’s effectiveness is its ability to utilize radiative cooling. The video explains Kirchhoff’s Law of Thermal Radiation, which states that an object’s emissivity (ability to emit radiation) is equal to its absorptivity (ability to absorb radiation) at the same wavelength. However, this paint is designed to be a highly efficient emitter within a specific range of infrared wavelengths known as the “atmospheric window.” This “window” is a part of the electromagnetic spectrum where Earth’s atmosphere produces almost no radiation, allowing the paint to effectively send its heat energy outwards into the extremely cold upper atmosphere with very little heat radiating back.
To demonstrate real-world applications, the presenter tests the cryo-paint on a small, insulated structure, comparing it to a black-painted roof. Inside the room, the cryo-painted roof resulted in air temperatures several degrees Fahrenheit cooler than the black-painted one, and the perceived heat was significantly reduced due to less radiant heat from the ceiling. Expanding on its versatility, the paint was also applied to a white tracksuit. Wearing the painted clothing in 90°F weather, the presenter reports feeling noticeably cooler, with infrared footage clearly showing the painted garments at a much lower temperature than the surrounding unpainted objects.
In conclusion, the video compellingly illustrates the potential of cryo-paint as an energy-efficient, passive cooling solution. By harnessing the coldness of the upper atmosphere through targeted radiative emission, it offers a transformative approach to cooling buildings and personal attire, significantly enhancing comfort and reducing energy consumption in hot environments. The presenter expresses amazement at its effectiveness and queries why such a groundbreaking product isn’t already a widely available commodity.
Video Description & Links
Description
The paint I used in the video: https://cryox.co/?srsltid=AfmBOopXe4jRQdqS2Ouq7P9IyXQtdE-d4ktQg0XolPAhr13OI1F-bDfS
Also here are some great videos by @Nighthawkinlight that go into more detail about these types of materials. https://youtube.com/playlist?list=PL1a2HkcVbmAWExiWT__qQypLEwkvijnIM&si=WljyHtAk_zC1wg4J
Tags
cooling technology, cryopaint, the action lab, radiative cooling paint, radiative cooling
URLs
- https://cryox.co/?srsltid=AfmBOopXe4jRQdqS2Ouq7P9IyXQtdE-d4ktQg0XolPAhr13OI1F-bDfS
- https://youtube.com/playlist?list=PL1a2HkcVbmAWExiWT__qQypLEwkvijnIM&si=WljyHtAk_zC1wg4J