R32吸气状态对变频压缩机效率的影响

制冷剂R32作为R22热门过渡替代制冷剂,运行排气温度高严重影响压缩机长时间运行的可靠性,湿压缩方法可以降低压缩机的排气温度,但也降低了压缩机的效率。通过实验对比研究在定压比变频和定频变压比工况下,不同吸气状态对滚动转子式压缩机效率的影响,得出等熵压缩效率和容积效率与吸气状态的变化关系。实验结果表明:吸气过热时,均能保持较高的等熵压缩效率和容积效率,过热度对其影响不大,吸气带液时压缩机效率的变化趋势与吸气过热时不同,应区分开;相对x=1,x=0.9时等熵压缩效率和容积效率分别降低约7%和5%,总体降幅较小。定频下,压比越大,压缩机效率降低幅度越大,定压下,频率越高,降低幅度越小;等熵压缩效率和综合效率系数的变化趋势相同。

Effects of Different R32 Suction Status on the Variable Frequency Compressor Efficiency

For refrigerant R32 as popular alternative refrigerant of R22, the high discharge temperature influences seriously the reliability of long time operation for compressor. The wet compression method can reduce the discharge temperature of compressor, but it also can reduce the compressor efficiency. Through the experiments under the condition of variable frequency with constant pressure ratio and the condition of variable pressure ratio with constant frequency, the effects of different suction state on the efficiency of rolling rotary compressor were studied, and the relationship between isentropic compression efficiency and volume efficiency with different suction states was summarized. The experimental results show that: when suction refrigerant is superheated, compressor can maintain a high isentropic compression efficiency and volume efficiency. The superheat degree has little effect on compressor efficiency. However, the change in the efficiency of the compressor with vapor-liquid mixture suction is different as suction refrigerant is superheated. Compared to x = 1, with x = 0.9, the isentropic compression efficiency and volumetric efficiency decreases by about 7% and 5%, respectively; the overall reduction is very small. With constant frequency, the greater the pressure ratio is, the larger the reduction in compressor efficiency. With constant pressure ratio, the higher the frequency is, the smaller the decrease. The trends of the isentropic compression efficiency and the comprehensive efficiency coefficient are consistent.