Analysis of refrigeration equipment system operation and introduction of energy-saving measures

Analysis of refrigeration equipment system operation and introduction of energy-saving measures

1. Economic analysis of refrigeration equipment system operation

The amount of cold produced by the refrigeration equipment is directly related to the operating conditions of the system. For the same compressor with the same structure, speed, and type of refrigerant, due to changes in operating conditions and different operation management, its cooling capacity and energy consumption Also changes.

　　 1. As the evaporation temperature decreases, the compression ratio of the compressor increases, and the energy consumption per unit of cold production increases. When the additional issuance temperature is lowered by 1℃, it will consume 3%-4% more electricity. Therefore, minimize the evaporation temperature difference and increase the evaporation temperature, which not only saves power consumption, but also increases the relative humidity of the cold room.

　　2. As the condensation temperature increases, the compression ratio of the compressor increases, and the energy consumption per unit of cold production increases. The condensing temperature is between 25-40°C, and every 1°C increase will increase power consumption by about 3.2%.

　　3. When the heat exchange surface of the condenser and the evaporator is covered with an oil layer, it will cause the condensation temperature to rise and the evaporation temperature to decrease, resulting in a decrease in cold production and an increase in power consumption. When a 0.1mm thick oil layer accumulates on the inner surface of the condenser, it will reduce the compressor’s cold production by 16.6% and increase power consumption by 12.4%; when the 0.1mm thick oil layer accumulates on the inner surface of the evaporator, in order to maintain a predetermined low temperature As required, the evaporation temperature will drop by 2.5°C and the power consumption will increase by 9.7%.

　　4. When air accumulates in the condenser, it will cause the condensing pressure to rise. When the non-condensable gas partial pressure reaches 1.96×105Pa, the compressor power consumption will increase by 18%.

　　 5. When the scale on the tube wall of the condenser reaches 1.5mm, the condensing temperature will increase by 2.8°C compared to the temperature before the scale, and the power consumption will increase by 9.7%.

6. The surface of the evaporator is covered with a layer of frost to reduce the heat transfer coefficient, especially when the outer surface of the fin tube is frosted, which not only increases the heat transfer resistance, but also makes the air flow through the fin difficult and reduces the appearance The 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 is about 70% before frosting after one month of operation.

　　7. The gas sucked by the compressor is allowed to have a certain degree of superheat, but the degree of superheat is too high, the specific volume of the sucked gas increases, the cold production is reduced, and the relative power consumption increases.

　　 8. When the compressor is frosted, close the suction valve quickly, drastically reduce the cold output and increase the power consumption.

　　 Through the above analysis, we can see that doing a good job in the management of refrigeration equipment operation is an important part of improving the economic benefits of refrigeration equipment systems.

　　 2. Energy-saving measures for refrigeration equipment operation

　　 1. Strengthen the operation and management of refrigeration equipment, and establish a refrigeration equipment power management and unit consumption statistics system. Conveniently assess the power consumption and material consumption quota, increase the necessary measuring instruments and appliances, carry out energy saving and technological transformation work, and consolidate the energy saving work from the system.

　　2. Correct operation and maintenance of refrigeration equipment:

　　2.1. Correctly control and adjust the liquid supply of the system, and avoid the occurrence of excessive humidity and overheating of the compressor suction.

　　2.2. Reasonably choose the number of compressors to operate, so that its cooling capacity matches the thermal load of the system.

　　2.3. According to process requirements and changes in outside temperature, properly adjust the number of fans and pumps in operation.

　　2.4. Regularly drain oil, air, defrost and remove scale, maintain good heat transfer effect of the equipment, and avoid excessively high condensation pressure and low evaporation pressure.

　　3. Improve the working conditions of refrigeration equipment as much as possible:

　　3.1. Improve water quality, slow down scaling, increase the condensation effect of the condenser, and lower the condensation temperature.

　　 3.2. When the motor load rate of the refrigeration equipment is below 0.4, the motor can be changed from △ to Y connection to improve the power factor, and it is required that the △ and Y connection can be automatically switched.

　　4. Try to use automatic control operation instead of manual operation as much as possible, so that the refrigeration equipment system can be operated under the best conditions, which can save power by 10-15%.