Performance characteristics of an R600a household refrigeration cycle with a modified two-phase ejector for various ejector geometries and operating conditions

Abstract

Even though a condenser outlet split (COS) ejector cycle offers several advantages over a standard two-phase ejector cycle, few experimental investigations on the performance of the COS ejector cycle are available in the literature. The objective of this study is to investigate the effects of the various ejector geometries on the performance of a small-sized household refrigeration cycle by using the refrigerant R600a under various operating conditions. The performance of the COS ejector cycle was measured and analyzed by varying the compressor speed, entrainment ratio (ER), nozzle position, and mixing section diameter. The enhancement in COP of the COS ejector cycle over that of the baseline cycle increased with the decrease in ER and increase in compressor speed, owing to the reduction in expansion loss. At a compressor speed of 45 Hz and an ER of 0.3, the maximum COP improvement of the COS ejector cycle with the optimum mixing section diameter over that of the baseline cycle was 6.8%. In addition, the optimum mixing section diameter for a given ER and compressor speed was proposed.