Mechanical Effic iency of a Variable Speed Scroll Compressor

This study presents the calculated mechanical efficiency of a variable speed compact scroll compressor for a wide range of synchronous-speed on an induction motor. The compression mechanism in the scroll compressor is quite different from that in the rolling-piston rotary compressor, and thus it is quite interesting to examine the difference in mechanical efficiency which is caused by the compression mechanism itself. From this point of view, the mechanical efficiency for the scroll compressor was calculated by using the dynamic analysis introduced in our previous studies, and finally the calculated results were compared with those for a rolling-piston rotary compressor with the same cooling capacity. This study concludes that a scroll compressor with optimum dimensions has the same high level of mechanical efficiency as a rolling-piston rotary compressor with the same cooling capacity, and that as the operating speed increases, the mechanical efficiency of the scroll compressor does not decrease as rapidly as that of the rolling-piston rotary compressor.