Latent Heat
Types of Latent Heat
Latent Heat of Fusion
- Energy required to phase change from solid → liquid
Latent Heat of Vaporization
- Energy required to phase change from liquid → gas
Latent Heat of Sublimation
- Energy required to phase change from solid → gas
Notes
The latent heat of vaporization is extremely useful for refrigeration. By compressing a refrigerant (e.g. R600-A) and passing it through a condenser under pressure, the liquid’s boiling point is reduced, making it very receptive to evaporating. By then passing the liquid through an evaporator, the refrigerant, now under reduced pressure, can absorb heat from the environment and change phase to a gas. This process is then repeated indefinitely.
The combination of a proper refrigerant and the refrigeration cycle allows for a coefficient of performance (COP) that is greater than 1. This is the ratio of input energy versus the amount of heat energy that is moved/pumped. A COP of 2-4 is common depending on ambient temperatures, etc.
Terms
Latent energy, heat of transformation, hidden energy
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