经济器对磁悬浮离心压缩机性能影响的研究

Study on Effects of Economizer on the Performance of Magnetic Bearing Centrifugal Compressor

制冷系统中使用经济器可以提高系统制冷量,但是中间补气使压缩机耗功增加,制冷循环中有效制冷剂流量降低,制冷系统的能效比并不会随着制冷量成正比增长,因此存在一个理论最优补气压力。本文通过实测一台带经济器制冷循环的水冷磁悬浮离心式机组在不同负荷运行情况,研究了经济器和补气压力对于水冷磁悬浮离心式压缩机性能及COP的影响。研究结果表明:磁悬浮压缩机的效率随着补气压力的升高出现先升后降的趋势;在所有工况下,调节补气压力都会提高效率,且存在一个最佳的补气压力使制冷系统的COP最优。

The cooling capacity could be increased by using the economizer in the refrigeration system, but the COP would not be improved in direct proportion because the compressor power would increase while compensating vapor in the process of compression, which would reduce mass flow rate in the cycle. Theoretically, there is an optimum superfeed pressure in the refrigeration system. In this paper, the performance of magnetic bearing centrifugal compressor was investigated by analyzing the operation of the water-cooled magnetic bearing centrifugal chiller with sub-cooler circuit economizer in different loads,and the influence of the superfeed pressure on the compressor efficiency and system COP was obtained. The results show that the compressor efficiency and COP will rise first and then will drop with the increasing superfeed pressure increasing. Under all conditions, the efficiency will be improved by adjusting superfeed pressure. There is an optimum superfeed pressure to obtain the best COP.