Development of Hermetic Carbon Dioxide Compressor

This study, which developed a laboratory prototype of a hermetic C02 compressor, was motivated by three primary factors. First, the C02 cycle is important because of global concern about ozone depletion and global wanning. Second, the leak tightness, efficiency, size and weight of hermetic motor-driven compressors make them preferable to open-type compressors for conventional residentiallcommercial air-conditioning. Third, compact and efficient hermetic compressors are necessary to develop an equivalently sized or compact system. The performance of the C02 compressor was compared with that of an R-22 compressor by using the test facility developed for the transcritical C02 cycle. Test results show the performance potential of the C02 compressor which is sized to match the conventional hermetic R-22 compressor. INTRODUCTION Though the transcritical C02 cycle has gained much attention recently, most research has focused on transportation applications where an open-type compressor is used. For transportation applications, Lorentzen and Petterson (1993) and Koehler et al. (1995) published experimental data showing superior perfonnance for C02 over that ofR-12 at lower ambient temperatures. For conventional residentiallcommercial air-conditioning, a hermetic motor-driven compressor has traditionally been used. A compact, efficient hermetic compressor is necessary to develop a compact system. Recently, Kruse (1996) and Fagerli (1996a) published experimental results on open-type C02 compressors, and Fagerli (1996b) published experimental results on a hermetic C02 compressor with an isentropic efficiency of 43%. In the present study, experimental tests were carried out with hermetic motor-driven compressors for R-22 and C02.