Reducing the Heat Exchange Efficiency of Heat Exchangers

Reducing the Heat Exchange Efficiency of Heat Exchangers

The thermal conductivity of lubricating oil is much lower than that of refrigerants (the thermal conductivity of common refrigeration oils is only 1/10 to 1/20 of that of refrigerants such as R22 and R410A). When the oil circulates with the refrigerant and adheres to the inner wall of evaporators and condensers, it will form an oil film on the heat exchange surface. This oil film acts as a thermal insulation layer, increasing the thermal resistance of heat exchange and significantly reducing the heat transfer efficiency of evaporators and condensers.

For evaporators, reduced heat exchange efficiency will lead to insufficient evaporation of the refrigerant, lower evaporation temperature, and even the appearance of liquid refrigerant entering the compressor (liquid hammer), which seriously endangers the safe operation of the compressor. For condensers, the decrease in heat dissipation capacity will cause the condensing pressure and temperature to rise, increasing the power consumption of the compressor and reducing the overall cooling capacity and energy efficiency ratio (EER) of the system.