In the evaporator the fluid steals heat from the environment and evaporates. For this process it needs a certain amount of heat. Overheating of the fluid is the heat it gains beyond what is necessary for complete evaporation. Therefore, overheating can be understood as the difference in the temperature of the fluid at the compressor inlet in relation to the temperature of the fluid that vaporizes in the evaporator. If the superheat is too high, there are problems with the compressor oil viscosity. If the superheat is too low, there is a danger of fluid entering the liquid form in the compressor.
