As the condensation temperature increases, the compressor compression ratio increases and the energy consumption per unit cooling capacity increases. For every 1°C added to the condensing temperature between 25°C and 40°C, power consumption increases by approximately 3.2 percent.

When the heat exchange surfaces of the condenser and evaporator are covered with a layer of oil, the condensation temperature increases and the evaporation temperature decreases, resulting in a reduction in cooling capacity and an increase in power consumption. When a 0.1mm thick oil layer accumulates on the inner and outer surface of the condenser, the cooling capacity of the compressor will be reduced by 16.6% and the power consumption will increase by 12.4%. When the oil is 0.1 mm thick inside and outside the evaporator, in order to maintain the predetermined low temperature requirements, the evaporation temperature drops by 2.5°C and the power consumption increases by 9.7.

The surface of the evaporator is covered with a layer of frost, which reduces the heat transfer coefficient. The outer surface of the fin tube is frosted, which not only increases the heat exchange resistance, but also makes the air flow between the fins difficult and reduces the appearance. Heat transfer coefficient and heat dissipation area. When the indoor temperature is below 0°C and the temperature difference between the two sides of the evaporator tube group is 10°C, the heat transfer coefficient of the evaporator after one month of operation before frost is about 70.