Compressor: Taking the R-22 refrigerant gas as an example, if we were to condense the refrigerant at atmospheric pressure, we would need to reduce its temperature to -41ºC. That is, its condensing temperature is not viable at atmospheric pressure. The role of the compressor is to increase the pressure of the refrigerant, increase its temperature and change its dew point. In this case, condensation takes place under high pressure and high temperature. A compressor draws in refrigerant as a low-pressure, low-temperature vapor and compresses it, increasing its pressure and temperature. This pressure is also important for the circulation of the refrigerant throughout the refrigeration circuit. The mechanical energy that the compressor uses to increase pressure is converted into thermal energy. The heat raises the temperature of the steam. It is important to note that the compressor is only used to pump refrigerant vapor.
Otherwise, if the refrigerant is liquid in the compressor, it can cause valve rupture or oil dilution, which can damage the bearings.
Condenser: Hot refrigerant vapor at high pressure and temperature is discharged into the condenser. A condenser is nothing more than a heat exchanger and can be air or water. When heat is transferred from a higher temperature substance to a lower temperature substance, the latent heat absorbed by the steam during evaporation plus the sensible heat absorbed by the steam during compression is transferred to the air (air condensation) or Water. (water condensation). Once the heat is removed from the refrigerant, it condenses and returns to a liquid state. The condenser subcools the liquid before leaving it and entering the expansion valve.
expansion device: As the liquid leaves the condenser and passes through the expansion device, the pressure drops to the evaporator pressure.
At this low pressure, a small portion of the liquid immediately evaporates, cooling the temperature of the remaining liquid to the evaporation temperature. As this temperature is lower than the temperature of the air or water that we are cooling, the heat removed by evaporating the refrigerant in the evaporator cools the air or water or associates.
Evaporator : The function of the evaporator is to cool ambient air or cooling water. Liquid refrigerant absorbs heat from the air or water, causing the refrigerant to evaporate. The refrigeration circuit is now complete for the refrigerant in vapor form, again drawn in by the compressor.