一、概况(一)CO_2作为制冷剂早在1866年成功用 CO_2制冷机制取商业用冰,发展到1930年,全世界80%的轮船采用 CO_2制冷机。后因 CFCs 良好的热力性能,才使 CO_2逐渐退出制冷领域(1950年最后一艘CO_2制冷船停止服役)。随着人们对环保问题的重视及跨临界制冷循环的提出,天然工质 CO_2又迎来第二个春天,其对 First, an overview (A) CO_2 as a refrigerant As early as 1866, the commercial ice with CO_2 refrigeration system successfully developed to 1930, 80% of the world’s ships using CO_2 refrigerator. Due to the good thermal performance of CFCs, CO2 was gradually withdrawn from the refrigeration field (the last CO_2 refrigeration ship ceased to serve in 1950). With people’s emphasis on environmental issues and the proposed transcritical refrigeration cycle, the natural refrigerant CO_2 ushered in the second spring, the right