A transcritical refrigeration cycle with carbon dioxide for bus air conditioning and transport refrigeration

摘要

The first part of this paper presents carbon dioxide air conditioning units which were installed in two city buses. The two buses were tested "on-the-road" during summer 1997 in Bad Hersfeld, Germany. By the end of 1997, the air condition systemsof the two buses had been running together for more than 860 hours proving that CO{sub}2 systems fulfill important on-the-road requirements. In the second part of this paper a laboratory prototype is discussed which used carbon dioxide as refrigerant fortransport refrigeration. An internal heat exchanger improves the cooling capacity but has no significant effect on the COP for ambient air temperatures of 30°C (86 F). The last part of the paper describes the design steps of the compressor used for bothbus air conditioning and transport refrigeration. The comparison of compressor versions 1 and 2 show significant improvements differences in the measured indicator diagrams mainly due to the modified discharge valves.