Scroll compressor, Three dimensional compression, Large capacity, Two-stage compression
Large capacity scroll compressor was developed for first stage of two-stage compression system. The developed compressor has larger displacement volume than our current models with same external dimension of compressor. Compressor with larger displacement volume has advantages to larger cooling capacity and less mechanical loss under the same cooling capacity because of less rotation speed. Also, extension of compressor capacity will be advantageous for application of low GWP refrigerants including HFOs, which are attracting attention recently, because they generally have low densities compared to current HFCs. To extend displacement volume, the authors adopted three dimensional compression mechanism (3D scroll) which has different scroll wrap heights with steps at tip and bottom of the scroll and compresses gas to axial direction as well as radial direction. 3D scroll has large capacity with higher outer wrap and maintains strength of wrap and end plate with lower inner wrap. In case of the developed compressor, by adopting 3D scroll and optimizing its involute parameters, the design volume ratio became more suited for two-stage compression system and its displacement volume is nearly twice than that current 2D scroll and about 1.3 times larger than current 3D scroll. This article describes characteristic features and test results of the developed compressor.