Solids
In some applications, solid materials are used as coolants. The materials require high energy to vaporize; this energy is then carried away by the vaporized gases. This approach is common in spaceflight, for ablative atmospheric reentry shields and for cooling of rocket engine nozzles. The same approach is also used for fire protection of structures, where ablative coating is applied.
Dry ice and water ice can be also used as coolants, when in direct contact with the structure being cooled.
Sublimation of water ice was used for cooling the space suits of astronauts in the Project Apollo.
Engine Coolants
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