Performance Characteristics Of Refrigeration Cycle Research Articles

Performance characteristics of refrigeration cycle with parallel compression economization

Thermodynamic analyses and economizer pressure optimizations of ammonia, propane and isobutane-based refrigeration cycles with parallel compression economization are presented in this article. Energetic and exergetic performance comparisons with transcritical CO2 cycle are presented as well. Results show that the optimum economizer mass fraction as well as COP improvement increase with increase in cycle temperature lift. The expression for optimum economizer pressure has been developed. Study shows that the performance improvements using parallel compression economization are strongly dependent on the refrigerant properties as well as the operating conditions. Using parallel compression economization, carbon dioxide yields maximum COP improvement of 31.9% followed by propane (29.8%), isobutane (27.2%) and ammonia (11.3%) for studies ranges. In spite of higher COP improvement, the cooling COP as well as second low efficiency for carbon dioxide is still significantly lower than that for others. Component-wise irreversibility distributions show the similar trends for all refrigerants except CO2. Employing parallel compression economization in refrigeration cycle not only improves the cooling COP but also increase the compactness of evaporator. Copyright © 2010 John Wiley & Sons, Ltd.

흡입관 열교환기를 이용한 탄화수소계 냉매용 냉동사이클의 성능 분석

본 논문은 R290, R600a, R1270과 같은 탄화수소계 냉매를 사용하는 냉동사이클의 효율에 대한 흡입관 열교환기의 영향을 고려하였다. 이러한 흡입관 열교환기는 냉동시스템의 성능을 향상시킬 수도 있지만, 성능을 저하시킬 수도 있다. 본 논문에서는 흡입관 열교환기를 가진 냉동사이클의 성능 특성을 파악하기 위해서 정상상태의 수학적 모델을 사용하였다. 그리고 탄화수소계 냉매유량, 흡입관 열교환기의 내관 직경, 길이, 유용도 등과 같은 운전조건의 영향을 분석하였다. 연구결과는 흡입관 열교환기의 내관 직경, 길이, 유용도, 탄화수소계 냉매의 질량유량은 냉동사이클의 상대냉동능력지수, 냉동능력, 압축일량에 영향을 미치는 것을 알 수 있었다. 따라서 이러한 영향을 상세히 파악하여, 흡입관 열교환기를 설치한 탄화수소계 냉매용 증기압축식 냉동사이클을 설계할 필요가 있다. This paper considers the influence of suction-line heat exchangers on the efficiency of a refrigeration cycle using hydrocarbon refrigerants such as R290, R600a and R1270. These suction-line heat exchangers can, in some cases, yield improved system performance while in other cases they degrade system performance. A steady state mathematical model is used to analyze the performance characteristics of refrigeration cycle with suction-line heat exchanger. The influence of operating conditions, such as the mass flowrate of hydrocarbon refrigerants, inner diameter tube and length of suction-line heat exchanger, to the performance of the cycle is also analyzed in the paper. Results showed that the mass flowrate of hydrocarbon refrigerants, inner diameter tube and length of suction-line heat exchanger, and effectiveness have an effect on the cooling capacity, compressor work and RCI(Relative Capacity Index) of this system. With a thorough grasp of these effect, it is necessary to design the compression refrigeration cycle of hydrocarbon refrigerants using suction-line heat exchanger.