Experimental analysis of a small DC air conditioner employing refrigerant R-134a, TC-12a or R-290

• Main Authors: Ching-Hung WU, 吳青鴻
• Other Authors: Jiann-Lin Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/8n4cpm

碩士 === 義守大學 === 機械與自動化工程學系 === 102 === CFC refrigerant has been banned from use since 1996 and the alternative was form HCFC to HFC, which unfortunately caused huge global warming effect. Recently environmentally-friendly HC refrigerant was proposed. This study aimed to apply HC refrigerant to a moveable DC air conditioner, which was composed of a DC24V 80Ah lead-acid battery, DC 24V compressor with 800-1200W refrigerating capacity and the capillary, to investigate its key parameters and performance characteristics in terms of R-134a as well as HC refrigerants, TC-12a and R-290. Furthermore, the problem of condensed water during air flow in the evaporator was solved by using the ultrasonic nebulizer as well as the fan of condenser. Parameters in this experiment include high and low pressures of the capillary, temperature drops of the evaporator and the condenser, and total current of the system. After analyzing measured data, we have concluded that: (1) For the air conditioner with the capillary of 1040mm long as expansion device and the fan speed of evaporator 6.89m/s, using R134a of 425g has the higher coefficient of performance than that of TC-12a of 350g; using TC-12a of 350g has the higher coefficient of performance than that of R-290 of 210g. (2) For the air conditioner with the capillary of 1900mm long, using TC-12a of 350g has the 13.53% higher coefficient of performance than that of R134a of 425g; using R-290 of 210g has the 5.99% lower coefficient of performance than that of R134a of 425g. In conclusion, it is feasible to use HC refrigerator instead of R-134a for the present air conditioner. However, R-290 is also practicable as cost and maintenance problems are under consideration.