Latent heat occurs in the refrigeration system during the phase change of the refrigerant. In a typical vapor compression refrigeration system, the refrigerant undergoes a continuous cycle of changing states between liquid and vapor as it absorbs and releases heat to achieve cooling.
The four main components of a vapor compression refrigeration system are:
Evaporator: The evaporator is where the refrigerant absorbs heat from the surroundings (air, water, or other substances) and evaporates from a liquid state to a vapor state. During this process, the refrigerant's latent heat is absorbed from the surrounding medium, cooling it down.
Compressor: The vaporized refrigerant from the evaporator enters the compressor. The compressor's primary function is to raise the pressure and temperature of the refrigerant, converting it from a low-pressure vapor to a high-pressure vapor.
Condenser: The high-pressure, high-temperature vapor then flows into the condenser. In the condenser, the refrigerant releases its latent heat to the surrounding air or water. As a result, the refrigerant condenses from a vapor state to a liquid state.
Expansion Valve (or Throttle Valve): After leaving the condenser, the high-pressure liquid refrigerant passes through the expansion valve or throttle valve. The expansion valve reduces the pressure of the refrigerant suddenly, causing it to undergo a rapid phase change from a high-pressure liquid to a low-pressure mixture of liquid and vapor. This sudden expansion further cools down the refrigerant, preparing it to absorb heat again in the evaporator.
This continuous cycle of evaporation (absorbing heat) in the evaporator and condensation (releasing heat) in the condenser is what allows the refrigeration system to transfer heat from a lower-temperature area (the evaporator) to a higher-temperature area (the condenser), resulting in cooling effects. The absorption and release of latent heat during these phase changes are vital to the refrigeration process.