Why Do Compressed Air Cans Get Cold?

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Shared April 2, 2019

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This video is about compressed air cans (aka gas dusters) and why they get cold when you spray them. They cool off because the refrigerant inside (1,1-difluoroethane) is under pressure and boils off when the pressure lowers, and energy lost to the latent heat of vaporization cools the can a lot. Difluoroethane normally boils at -25°C (-13°F), but under ~6 atm (6 bar, 600 kpa) it is a liquid at room temperature. The gas also cools off slightly due to the Joule-Thompson effect of fluid expansion through a throttled valve. Difluoroethane is heavier than air and water soluble, so it is recommended to use it in a ventilated environment to clean your keyboard, etc. Also, 1,1-difluoroethane is a potent greenhouse gas. It is also known as Freon 152a, Ethylidene difluoride, Ethylidene fluoride, HFC-152a, R-152a, and DFE.

Thanks to Tino and Hannah!


CRC Air Duster Safety Data Sheet

Latent Heat of vaporization

1,1-difluoroethane chemical and physical properties

1,1-difluoroethane on wikipedia

Free Expansion of Real Gases, Goussard, 1993

Joule-Thompson Expansion Course Notes

Properties of 1,1-difluoroethane

Medical Effects of difluoroethane

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