The cooling capacity of the chiller is directly related to the operating conditions of the system. For compressors with the same structure, the same speed, and the same refrigerant, due to changes in operating conditions, different cooling capacity and energy consumption, their operation management is also different and changes accordingly.
1. As the evaporation temperature decreases, the compression ratio of the compressor increases, and the energy consumption per unit of production cooling increases.
When the evaporation temperature drops by 1°C, it consumes 3% to 4%. Therefore, minimize the evaporation temperature difference and increase the evaporation temperature, which not only saves energy, but also increases the relative humidity of the cold room.
2. As the condensing temperature increases, the compressor compression ratio increases, and the energy consumption per unit of refrigeration capacity increases.
The condensing temperature is between 25°C and 40°C for every 1°C increase, the power consumption increases by about 3.2%.
3. When the heat exchange surface of the condenser and the evaporator is covered with an oil layer, the condensation temperature increases and the evaporation temperature decreases, resulting in a decrease in cooling capacity and an increase in power consumption.
When a 0.1mm thick oil layer accumulates on the inner surface of the condenser, the cooling capacity of the compressor will decrease by 16.6 and the power consumption will increase by 12.4. When the oil is a 0.1mm thick inner surface type evaporator, in order to maintain the predetermined low temperature requirement, the evaporation temperature is reduced by 2.5°C and the power consumption is increased by 9.7.
4. When air accumulates in the condenser, the pressure of the condenser will increase.
When the partial pressure of non-condensable gas reaches 1.96105Pa, the power consumption of the compressor needs to increase by 18.
5. When the scale of the condenser wall reaches 1.5 mm, the condensing temperature rises by 2.8°C before the temperature calibration, and the power consumption increases by 9.7.
6. The surface of the evaporator is covered with a layer of frost, which reduces the heat transfer coefficient.
Especially 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 lower than 0°C, when the temperature difference between the two sides of the evaporator tube group is 10°C, the heat transfer coefficient of the evaporator after frosting is about 70 for a month before working.
7. The gas sucked by the compressor allows a certain degree of overheating, but if the overheating is too large, the specific volume of the sucked gas will increase, the cooling capacity will decrease, and the relative power consumption will increase.
When compressing the frost, quickly close the small suction valve, drastically reduce the cooling capacity, and relatively increase the power consumption.
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