冷凝器的工作原理(li)

    氣(qi)(qi)體通(tong)(tong)過一根長管(通(tong)(tong)常(chang)盤繞成螺線管)向周圍空氣(qi)(qi)散熱。銅等金屬具有(you)很強的(de)導熱性(xing)，通(tong)(tong)常(chang)用(yong)于輸送蒸汽。為了提高(gao)冷(leng)凝(ning)器的(de)效率，經常(chang)在管道上增加具有(you)良好導熱性(xing)能的(de)翅片，以(yi)增加散熱面積，從而(er)加速(su)散熱，并通(tong)(tong)過風扇加速(su)空氣(qi)(qi)對流帶(dai)走熱量。

    普通冰箱(xiang)的制冷原理(li)是壓(ya)(ya)(ya)縮機將工(gong)作介質(zhi)(zhi)從低(di)(di)溫(wen)低(di)(di)壓(ya)(ya)(ya)氣(qi)體(ti)壓(ya)(ya)(ya)縮成(cheng)高(gao)溫(wen)高(gao)壓(ya)(ya)(ya)氣(qi)體(ti)，然(ran)后通過(guo)冷凝(ning)器將工(gong)作介質(zhi)(zhi)冷凝(ning)成(cheng)中溫(wen)高(gao)壓(ya)(ya)(ya)液體(ti)。經(jing)節流閥節流后，工(gong)作介質(zhi)(zhi)變(bian)成(cheng)低(di)(di)溫(wen)低(di)(di)壓(ya)(ya)(ya)液體(ti)。低(di)(di)溫(wen)低(di)(di)壓(ya)(ya)(ya)液態工(gong)質(zhi)(zhi)被送到(dao)蒸(zheng)發(fa)器，在(zai)蒸(zheng)發(fa)器中吸熱蒸(zheng)發(fa)成(cheng)低(di)(di)溫(wen)低(di)(di)壓(ya)(ya)(ya)蒸(zheng)汽(qi)，再被送到(dao)壓(ya)(ya)(ya)縮機，完成(cheng)制冷循環。

    一種單級蒸汽壓縮制冷(leng)系(xi)統(tong)，由制冷(leng)壓縮機、冷(leng)凝器、節流閥和(he)蒸發器四個基本部件通過管道依次連接組成一個封閉系(xi)統(tong)，制冷(leng)劑(ji)在系(xi)統(tong)中不斷循環流動，改(gai)變狀態，與外(wai)界進行(xing)熱交換。

    蒸發器的工作原(yuan)理

    加(jia)熱(re)(re)室由垂直(zhi)管(guan)(guan)(guan)束組成(cheng)，中(zhong)(zhong)(zhong)(zhong)(zhong)間有一個直(zhi)徑(jing)較大的(de)中(zhong)(zhong)(zhong)(zhong)(zhong)央循環(huan)管(guan)(guan)(guan)，其他直(zhi)徑(jing)較小(xiao)(xiao)的(de)加(jia)熱(re)(re)管(guan)(guan)(guan)稱為沸騰(teng)管(guan)(guan)(guan)。由于(yu)(yu)中(zhong)(zhong)(zhong)(zhong)(zhong)心(xin)循環(huan)管(guan)(guan)(guan)較大，單位體(ti)積溶液所占的(de)傳熱(re)(re)面積小(xiao)(xiao)于(yu)(yu)沸騰(teng)管(guan)(guan)(guan)中(zhong)(zhong)(zhong)(zhong)(zhong)單位溶液所占的(de)傳熱(re)(re)面積，即(ji)中(zhong)(zhong)(zhong)(zhong)(zhong)心(xin)循環(huan)管(guan)(guan)(guan)中(zhong)(zhong)(zhong)(zhong)(zhong)溶液的(de)加(jia)熱(re)(re)程度與其他加(jia)熱(re)(re)管(guan)(guan)(guan)不(bu)同，因此(ci)沸騰(teng)管(guan)(guan)(guan)中(zhong)(zhong)(zhong)(zhong)(zhong)汽液混合(he)物(wu)的(de)密(mi)度小(xiao)(xiao)于(yu)(yu)中(zhong)(zhong)(zhong)(zhong)(zhong)心(xin)循環(huan)管(guan)(guan)(guan)中(zhong)(zhong)(zhong)(zhong)(zhong)溶液的(de)密(mi)度。

    此外，上升(sheng)(sheng)蒸(zheng)(zheng)汽的(de)(de)向上抽吸將導(dao)致蒸(zheng)(zheng)發器中(zhong)的(de)(de)溶液形(xing)成(cheng)從中(zhong)央(yang)循環(huan)管下降并(bing)從沸騰管上升(sheng)(sheng)的(de)(de)循環(huan)流。這(zhe)種(zhong)循環(huan)主要(yao)是(shi)由溶液的(de)(de)密度差引起的(de)(de)，所(suo)以稱之為自然(ran)循環(huan)。這(zhe)種(zhong)效果(guo)有利于提高(gao)蒸(zheng)(zheng)發器中(zhong)的(de)(de)傳熱效果(guo)。

    在制(zhi)冷(leng)系統中，蒸(zheng)發器(qi)、冷(leng)凝器(qi)、壓縮(suo)機(ji)和節流閥是(shi)(shi)制(zhi)冷(leng)系統的(de)四個重要組(zu)成部分(fen)，其中蒸(zheng)發器(qi)是(shi)(shi)輸送(song)冷(leng)量的(de)設(she)備。制(zhi)冷(leng)劑吸(xi)收被(bei)冷(leng)卻物體的(de)熱(re)量實現(xian)制(zhi)冷(leng)。壓縮(suo)機(ji)是(shi)(shi)心臟，在吸(xi)入、壓縮(suo)和輸送(song)制(zhi)冷(leng)劑蒸(zheng)汽方面(mian)發揮作用(yong)。

    為了(le)釋放熱量，蒸發器中吸(xi)收的熱量與壓(ya)縮機(ji)功轉換的熱量一起傳遞(di)給冷(leng)卻介質。節(jie)流閥對制(zhi)冷(leng)劑進行節(jie)流和降壓(ya)，控(kong)制(zhi)和調節(jie)流入蒸發器的制(zhi)冷(leng)劑液體量，并將系統分為兩部分:高壓(ya)側(ce)和低壓(ya)側(ce)。

    在實際的制冷系統中，除(chu)了(le)上述四個部件之外，通(tong)常還有一些(xie)輔助設(she)備，如電磁(ci)閥、分(fen)配器(qi)、干燥器(qi)、收(shou)集器(qi)、易熔塞、壓力(li)控制器(qi)和其他部件，它們(men)的設(she)置是為了(le)提高運行的經濟性(xing)(xing)、可(ke)靠性(xing)(xing)和安全性(xing)(xing)。