Journal of Advanced Marine Engineering and Technology

The Korean Society of Marine Engineering (한국마린엔지니어링학회)
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Mass flow rate ratio analysis for optimal refrigerant charge of a R744 and R404A cascade refrigeration system

R744-R404A 캐스케이드 냉동시스템의 최적 냉매 충전을 위한 질량유량비 분석

  • Oh, Hoo-Kyu (Department of Refrigeration and Air-Conditioning Engineering, Pukyong National University) ;
  • Son, Chang-Hyo (Department of Refrigeration and Air-Conditioning Engineering, Pukyong National University) ;
  • Jo, Hwan (Graduate School of Refrigeration and Air-Conditioning Engineering, Pukyong National University) ;
  • Jeon, Min-Ju (Department of Refrigeration and Air-Conditioning Engineering, Pukyong National University)
  • Received : 2013.07.23
  • Accepted : 2013.09.11
  • Published : 2013.09.30
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Abstract

In this paper, the influences of several factors, such as subcooling, superheating degree, internal heat exchanger efficiency, and etc. to the optimal amount of refrigerant charge are investigated for the case of R744-R404A cascade refrigeration system. Refrigerants used in the cascade refrigeration system are R404A in high temperature cycle and R744 in the low temperature cycle. The main results are summarized as follows : The mass flow rate ratio decreases with increasing subcooling, superheating degree and internal heat exchanger efficiency in the high temperature cycle, and evaporating temperature and compression efficiency in the low temperature cycle. And the mass flow rate ratio decreases with decreasing temperature difference of cascade heat exchanger and evaporating, condensing temperature in the high temperature cycle, and subcooling, superheating degree and internal heat exchanger efficiency in the low temperature cycle.

본 논문은 R744-R404A 캐스케이드 냉동시스템의 최적 냉매 충전을 위해 과냉도, 과열도, 내부열교환기 효율 등에 대한 영향을 분석한 것이다. 연구에 사용된 캐스케이드 냉동시스템의 고온 사이클에는 R404A, 저온 사이클에는 R744를 적용하였다. 그 주요 결과는 다음과 같다 : 고온 사이클의 과냉도, 과열도, 내부열교환기 효율과 저온 사이클의 증발온도와 압축효율은 크게 할수록 질량유량비가 작게 나타났다. 그리고 캐스케이드 온도차와 고온 사이클의 증발온도, 응축온도와 저온 사이클의 과냉도, 과열도, 내부열교환기 효율은 작을수록 질량유량비가 작게 나타났음을 확인하였다.

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