不同工作流體應用於空調熱管熱交換器之性能研究

Investigation of HVAC Heat Pipe Exchanger Performance by Using Various Working Fluids

李鎔鈞(Rong-Jyun Li)

指導教授 ： 柯明村

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(2012年)

摘要

隨著世界各國對於環境保護議題日趨重視，溫室氣體排放量的減少已成為因應全球氣候暖化共同推行的目標，而碳氫冷媒的選用已成為近期必然趨勢。本研究主要針對熱管熱交換氣換裝三種不同冷媒工作流體進行各項性能測試，實驗改變外氣流道入口乾球溫度由23℃至33℃及回收冷空氣流道質量流率由0.18 kg/s至0.66 kg/s，探討換裝R-600a碳氫冷媒比較R-22冷媒及R-134a冷媒其各種熱性能表現。進而針對熱管空調箱兩流道入出口溫差、熱交換效率、熱阻及管壁溫度進行比較與分析。
實驗結果顯示，三種冷媒工作流體其外氣乾球溫度分別與熱管入出口溫差及熱管熱交換效率成正比關係。而質量流率均與熱管入出口溫差及熱管冷凝端熱交換效率成反比關係。比較三者後發現，於外氣入口乾球溫度23℃及28℃狀態下，使用R-600a冷媒工作流體之熱管具有最佳熱交換效率5%及32%，於較高外氣入口乾球溫度33℃狀態下，使用R-22冷媒工作流體之熱管具有最佳熱交換效率40%。由上述結果可發現，於較低外氣乾球溫度時，R-600a冷媒工作流體具足夠能力作為取代R-22冷媒及R134a冷媒之另一種選擇。

關鍵字

熱管熱交換器 ； 熱交換效率 ； 碳氫冷媒 ； 溫室效應

並列摘要

With increasingly recognizing environmental protection by many countries of the world, one of the key activities to deal with global warming is to reduce emissions of greenhouse gases. The choice of hydrocarbon refrigerants has become an inevitable trend. This dissertation is to study performance of heat pipe exchanger with various refrigerant. Investigation of thermal performance of heat pipe exchanger is executed from R-22 and R-134a to hydrocarbon refrigerant R-600a with changes of outside air inlet dry bulb temperature with 23℃－33℃, and changes of the ratios of mass flow rate of return to fresh air with 1－3.66. Then it compares and analyzes the temperature changes of fresh air and return air, effectiveness of heat exchanger at evaporator and condenser side and wall temperature of heat pipe exchanger.
The experimental results show that the effectiveness and temperature changes of fresh and return air increased with the increase of inlet temperature. The effectiveness and temperature changes of fresh and return air are inverse proportional to the ratios of mass flow rate of return to fresh air. After comparison of the three working fluids, at the outside air inlet dry bulb temperature 23℃ and 28℃, the refrigerant R-600a heat pipe evaporation side has the best efficiency with 5% and 32%, respectively. At the outside air inlet dry bulb temperature 33℃, the refrigerant R-22 heat pipe evaporation side has the best efficiency with 40%. From the study, as the outside air inlet dry bulb temperature is low,it is expected to be a good alternative to replace R-22 and R-134a with hydrocarbon refrigerant R-600a.

並列關鍵字

heat pipe exchanger ； effectiveness ； hydrocarbon refrigerant ； global warming

參考文獻

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