制冷劑

制(zhi)(zhi)(zhi)(zhi)冷(leng)機中(zhong)(zhong)完成熱(re)力循(xun)環(huan)的(de)(de)(de)(de)(de)工(gong)(gong)(gong)(gong)質。它(ta)在(zai)(zai)(zai)(zai)低(di)溫下吸(xi)取被冷(leng)卻物體(ti)的(de)(de)(de)(de)(de)熱(re)量，然后(hou)在(zai)(zai)(zai)(zai)較高溫度(du)下轉移給冷(leng)卻水或(huo)(huo)空(kong)氣(qi)(qi)(qi)(qi)。在(zai)(zai)(zai)(zai)蒸氣(qi)(qi)(qi)(qi)壓(ya)(ya)縮式(shi)制(zhi)(zhi)(zhi)(zhi)冷(leng)機中(zhong)(zhong)，使用(yong)在(zai)(zai)(zai)(zai)常溫或(huo)(huo)較低(di)溫度(du)下能液(ye)化的(de)(de)(de)(de)(de)工(gong)(gong)(gong)(gong)質為制(zhi)(zhi)(zhi)(zhi)冷(leng)劑(ji)，如(ru)氟利(li)昂（飽(bao)(bao)和(he)碳氫化合(he)物的(de)(de)(de)(de)(de)氟、氯、溴衍生物），共(gong)沸(fei)混(hun)合(he)工(gong)(gong)(gong)(gong)質（由兩種氟利(li)昂按一定(ding)比(bi)例混(hun)合(he)而(er)成的(de)(de)(de)(de)(de)共(gong)沸(fei)溶液(ye)）、碳氫化合(he)物（丙烷、乙烯等(deng)）、氨等(deng)；在(zai)(zai)(zai)(zai)氣(qi)(qi)(qi)(qi)體(ti)壓(ya)(ya)縮式(shi)制(zhi)(zhi)(zhi)(zhi)冷(leng)機中(zhong)(zhong)，使用(yong)氣(qi)(qi)(qi)(qi)體(ti)制(zhi)(zhi)(zhi)(zhi)冷(leng)劑(ji)，如(ru)空(kong)氣(qi)(qi)(qi)(qi)、氫氣(qi)(qi)(qi)(qi)、氦氣(qi)(qi)(qi)(qi)等(deng)，這些氣(qi)(qi)(qi)(qi)體(ti)在(zai)(zai)(zai)(zai)制(zhi)(zhi)(zhi)(zhi)冷(leng)循(xun)環(huan)中(zhong)(zhong)始(shi)終為氣(qi)(qi)(qi)(qi)態(tai)；在(zai)(zai)(zai)(zai)吸(xi)收式(shi)制(zhi)(zhi)(zhi)(zhi)冷(leng)機中(zhong)(zhong)，使用(yong)由吸(xi)收劑(ji)和(he)制(zhi)(zhi)(zhi)(zhi)冷(leng)劑(ji)組成的(de)(de)(de)(de)(de)二元溶液(ye)作為工(gong)(gong)(gong)(gong)質，如(ru)氨和(he)水、溴化鋰 （分子式(shi)：LiBr。白色(se)立(li)方(fang)晶(jing)系結晶(jing)或(huo)(huo)粒狀粉末(mo)，易溶于(yu)水）和(he)水等(deng)；蒸汽噴射(she)式(shi)制(zhi)(zhi)(zhi)(zhi)冷(leng)機用(yong)水作為制(zhi)(zhi)(zhi)(zhi)冷(leng)劑(ji)。制(zhi)(zhi)(zhi)(zhi)冷(leng)劑(ji)的(de)(de)(de)(de)(de)主要技術指標有飽(bao)(bao)和(he)蒸氣(qi)(qi)(qi)(qi)壓(ya)(ya)強、比(bi)熱(re)、粘度(du)、導熱(re)系數、表面張力等(deng)。1960年以后(hou)，人(ren)們對(dui)非共(gong)沸(fei)混(hun)合(he)工(gong)(gong)(gong)(gong)質的(de)(de)(de)(de)(de)應(ying)用(yong)進(jin)行了(le)大量的(de)(de)(de)(de)(de)試驗研(yan)究，并(bing)已將其用(yong)于(yu)天然氣(qi)(qi)(qi)(qi)的(de)(de)(de)(de)(de)液(ye)化和(he)分離等(deng)方(fang)面。應(ying)用(yong)非共(gong)沸(fei)混(hun)合(he)工(gong)(gong)(gong)(gong)質單級壓(ya)(ya)縮可得到很低(di)的(de)(de)(de)(de)(de)蒸發溫度(du)，且可增加(jia)制(zhi)(zhi)(zhi)(zhi)冷(leng)量，減少功耗。 它(ta)的(de)(de)(de)(de)(de)性質直接關系到制(zhi)(zhi)(zhi)(zhi)冷(leng)裝置的(de)(de)(de)(de)(de)制(zhi)(zhi)(zhi)(zhi)冷(leng)效果、經濟性及(ji)運(yun)行管(guan)理，因而(er)對(dui)制(zhi)(zhi)(zhi)(zhi)冷(leng)劑(ji)性質要求(qiu)的(de)(de)(de)(de)(de)了(le)解是不容(rong)忽視的(de)(de)(de)(de)(de)。