混合冷媒(R-32/R-134a)在二階自動階層式冷凍系統之研究

Abstract

本論文為設計具有二階式自動階層之冷凍系統，此冷凍系統採用工作流體為混合冷媒R-32/R-134a（30/70 重量比），系統中利用兩組相分離器與中間熱交換器，進行了兩次的液氣相分離與熱交換，並使最後流進蒸發器內的低沸點高潛熱冷媒R-32濃度可以提高，藉此可以獲得較低溫的蒸發環境與冷凍能力。 實驗結果顯示混合冷媒進行二階自動階層循環時壓縮功比一階自動階層循環提昇了2.14 %， COP值可達到2.21，比一階自動階層高出4.25 %，最低溫可以達到-51℃，比一階自動階層更降低10℃，而且冷凝壓力與蒸發壓力會低於一階自動階層循環。本冷凍系統只需一台1.5匹馬力壓縮機即可提供足夠所需動力。

The objective of this research is to design a two auto-cascades refrigeration system with refrigerant mixture R-32/R-134a in which two phase separators and two heat exchangers are used to raise the concentration of the richer R-32 mixture flow through the evaporator in order to achieve the low temperature cooling , only utilize a 1.5HP compressor to support system power consumption. In comparison with the one-cascade system , test results for a R-32/R-134a(30/70 wt%) two cascades loop , showed an increase of only 2.14 % in the power consumption , and a cop valve 2.21 with an increment of 4.25% , as well as evaporator temperature of -51℃ . Also the condensation pressure and evaporation pressure in this two-cascade loop were much lower than those in one-cascade loop . The advantage of this system is that it needs only one 1.5 hp compressor to fulfil all the foregoing achievements .