都市月亮飘飘
Refrigeration（制冷）
制冷，是使某一空间或物体的温度降到低于周围环境温度，并保持在规定低温状态的一门科学技术，它随着人们对低温条件的要求和社会生产力的提高而不断发展。
常用制冷剂：
现在一般采用的是水，氨，CO2，R12，R22，R134a,R404,R407C，R410和R600a等制冷剂，格力使用R290，佳冰，中炜制冷公司推出R433b,福瑞至制冷公司推出ER445系列制冷，都是更节能、环保、高效的制冷剂，俗称碳氢制冷剂，无毒，不会对臭氧层产生任何破坏。但是由于都是烷类，都具有可燃与爆炸性质。
扩展资料：
制冷系统
制冷系统由4个基本部分即压缩机、冷凝器、节流部件、蒸发器组成。由铜管将四大件按一定顺序连接成一个封闭系统，系统内充注一定量的制冷剂。一般的空调用制冷剂为氟里昂，以往通常采用的是R22，有些空调的氟里昂已经采用新型的环保型制冷剂R407。
参考资料来源：百度百科-制冷
最美遇见微风
China has many ski fields and the skating rink. If you want to ski, you can go to Shanghai, Heilongjiang, and so on , there is many ski fields. If you want to ice-skate,you can go to Beijing, Harbin and so on , there is many skating rinks. the ice-skating, the ski is a very happy things.
sally7juicy
there're many skee and skate court in China.If you want to go skating,you can go to such cities like Shanghai and Heilongjiang which have lots of skate court.If you want to skee,Beijing and Harbin is your best choice because many skee courts locate there.Skee and skate are funny things!
