천연냉매를 이용한 냉동장치의 성능 특성에 관한 연구

Abstract

Ammonia can be used in the wide temperature range and it has quite good merits as a refrigerant due to a great COP and heat transfer rate, moreover high critical pressure and high critical temperature. But also it has the characteristic of toxicity, inflammability and explosiveness. Therefore, in this study, we will find the most suitable operating condition of Shell & Tube type heat exchanger with ammonia refrigerant. The result of performance characteristic test according to condensing pressure and superheat temperature is as following. we found that as the condensing pressure was raised at each uniformity degree of superheat condition, the mass flow rate of refrigerant was decreased due to increase of compression ratio and lowering of volume efficiency. At each uniformity condensing pressure condition, Shell & Tube type heat exchanger had slight change in a capacity of evaporator and capacity of evaporator was decreased according as condensing pressure and degree of superheat were getting higher. It revealed that Shell & Tube type heat exchanger was applicable to the ammonia refrigeration system, it seemed possible to have some economic profit and to solve the environment problem.