HFO冷媒應用於準二級空氣源熱泵熱水系統製熱性能之研究

Performance Investigation of Quasi-Two Stage Air-Source Heat Pump Water Heater Using HFO Refrigerants

張智閔(Chi-Min Chang)

指導教授 ： 李宗興

國立臺北科技大學/機電學院/能源與冷凍空調工程系碩士班/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00044

摘要

隨著蒙特婁議定書與京都議定書對於冷媒ODP (Ozone Depletion Potential)與GWP (Global Warming Potential)值的限制，尋找適合的冷媒應用於系統當中值得被研究。使用單級蒸氣壓縮冷凍循環系統在低溫操作條件下運轉時會面臨以下問題: 壓縮機之壓縮比過大、蒸發器之入口乾度變大、及壓縮機排氣溫度升高，這些都會使得系統整體的性能下降。因此在低溫環境(-5℃~-25℃)時，如何提升熱泵的性能值得探討。所以本文主要研究目的為:藉由理論模擬方式，以具有節能器之準二級空氣源熱泵熱水系統，在相同壓縮機條件下，以各項製熱性能探討HFO冷媒替代R134a的可行性評比。其中製熱性能包括：壓縮機排氣溫度、製熱能力、壓縮機消耗功率以及製熱性能係數。其中HFO冷媒本文使用R1234yf與R1234ze(E)，所考量之操作條件為冷凝溫度40℃~50℃蒸發溫度-10℃~-25℃。
研究結果發現:經過R1234yf與R1234ze(E)兩種冷媒綜合評比，發現R1234yf冷媒較R1234ze(E)適用於替代R134a，做為準二級熱泵熱水系統之中程冷媒。R1234yf製熱性能係數平均比R134a高出4.01%，壓縮機排氣溫度平均減少14.4℃，本文所得之結果與Spatz and Minor [18]觀點相符。

關鍵字

準二級熱泵熱水系統 ； HFO冷媒 ； 渦卷式壓縮機

並列摘要

As the restrictions on refrigerant by Montreal Protocol and Kyoto Protocol in ODP (Ozone Depletion Potential) and GWP (Global Warming Potential), to find a suitable refrigerant used in systems are worthy of study. While single stage air source heat pump water heater runs in conditions of low ambient temperature (-5℃~-25℃), it will face some problems. Such as: Compression ratio of the compressor will be oversized, the evaporator inlet quality will increase, and the discharge temperature of compressor will increase. These will make the overall system performance degradation. Therefore, if heat pump runs in conditions of low ambient temperature, it can overcome the above problem, and make the high efficiency, it should be investigated. The objective of this study is, through theory simulation parametric analysis for quasi-two stage air source heat pump system with economizer in the same compressor by R134a and HFOs refrigerants, to investigate performance under different operating conditions. To investigate the feasibility for HFOs as an alternative refrigerant to R134a. And HFO refrigerants which are R1234yf and R1234ze(E). The operating conditions of the condensing temperature is 40℃~50℃, and the evaporation temperature is -10℃~-25℃.The results show that: Comprehensive appraisal of R1234yf and R1234ze(E), the result shows that R1234yf is suitable than B to replace R134a for medium refrigerant of quasi-two stage heat pump system The refrigerant using R1234yf can increase the coefficient of performance about average 4.01% than R134a, and the discharge temperature of compressor reduced average 14.4℃. The obtained result of this study equivalent to Spatz and Minor [18].

並列關鍵字

quasi-two stage heat pump system ； HFO refrigerants ； scroll compressor

參考文獻

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