Latent heat is the energy required to change a liquid into a vapour at a constant temperature.

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Latent heat is the energy required to change a liquid into a vapour at a constant temperature.

Latent heat is the energy involved in changing the state of a substance without changing its temperature. For vaporization, the energy required to turn a liquid into a vapour at a constant temperature is the latent heat of vaporization. This energy goes into breaking intermolecular forces so liquid molecules become gas, while the temperature stays the same during the phase change. This is an endothermic process, meaning heat must be added. In HVAC contexts, this quantity helps predict how much energy the evaporator must supply to vaporize the refrigerant. The other ideas describe different concepts: energy released when a vapor condenses is latent heat of condensation, the reverse process, which releases energy rather than requires it. Cooling a gas to ambient temperature is sensible cooling, which lowers temperature without a phase change. The energy used to compress a refrigerant is mechanical work to increase pressure and temperature, not latent heat associated with a phase change.

Latent heat is the energy involved in changing the state of a substance without changing its temperature. For vaporization, the energy required to turn a liquid into a vapour at a constant temperature is the latent heat of vaporization. This energy goes into breaking intermolecular forces so liquid molecules become gas, while the temperature stays the same during the phase change. This is an endothermic process, meaning heat must be added. In HVAC contexts, this quantity helps predict how much energy the evaporator must supply to vaporize the refrigerant.

The other ideas describe different concepts: energy released when a vapor condenses is latent heat of condensation, the reverse process, which releases energy rather than requires it. Cooling a gas to ambient temperature is sensible cooling, which lowers temperature without a phase change. The energy used to compress a refrigerant is mechanical work to increase pressure and temperature, not latent heat associated with a phase change.

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