20世纪已经结束,现在已跨入新世纪。回顾过去的百年,暖通空调,尤其是空调制冷技术诞生并取得长足进步。美国工程院(机械工程师学会)分别评出的20世纪最伟大的工程技术成就20项(或10项)中均将空调制冷技术列为其中之一。因为有了这项技术,无论是在最热或最冷的地方都有人类在工 The twentieth century is over, and now it has entered a new century. Recalling the past century, HVAC, especially air-conditioning and refrigeration technology was born and made significant progress. Air conditioning and refrigeration technologies are among the 20 (or 10) of the greatest engineering achievements of the 20th century respectively reviewed by the American Academy of Engineering (Institute of Mechanical Engineers). Because of this technology, human beings are working whether in the hottest or coldest places