Some people say that the compressor of industrial chillers is not good when the temperature is high, and it is harmful when it is overheated. In fact, we can look at it this way. Overheating can be said to have advantages and disadvantages, so how should we overheat reasonably? Today we will take a closer look at the overheating of industrial chillers.
Determining the working parameters of the refrigeration cycle is to determine the working temperature and working pressure of the refrigerant, one of which includes: the determination of the "heart" of the industrial chiller-the suction temperature of the refrigeration compressor.
The temperature of the suction gas of the refrigeration compressor is always higher than the evaporating temperature, and the difference between the two is called superheat. Overheating is sometimes harmful and sometimes beneficial. The degree of superheat should be determined according to the evaporating temperature, the superheat in the suction pipe, the type of refrigerant and the type of refrigeration cycle. It can be determined according to the superheat specified by the various nominal working conditions of the refrigeration compressor, or according to the following experience determine.
The refrigeration system generally hopes to have a certain degree of suction superheat, which can improve the economy of the cycle and ensure the normal operation of the refrigeration system. Therefore, the degree of superheat can be determined according to the following principles.
1. If the chiller adopts a thermal expansion valve, the superheat of the gas at the outlet of the evaporator is 3～8℃;
2. For water-cooled/air-cooled chillers with single-stage compression and double-stage compression, the suction temperature of the high-pressure stage should not exceed 15°C, but it should not be too low;
3. The allowable suction temperature of the low-pressure stage of the two-stage compression chiller is related to the performance of the gas-liquid heat exchanger and the cold loss of the suction pipeline, which is generally 30-40°C higher than the evaporation temperature;
4. In the gas-liquid heat exchanger, the gas outlet temperature is 5-10℃ lower than the liquid inlet temperature;
5. The suction superheat of the low temperature part of the cascade chiller refrigeration system ranges from 12 to 63°C. The lower value is used when the evaporation temperature is higher, and the larger value is used otherwise. If the gas-liquid heat exchanger cannot reach this degree of superheating, an additional gas-gas heat exchanger can be used to increase the suction temperature.