• 태양에너지
• /
• 제15권3호
• /
• pp.75-90
• /
• 1995

본 논문은 가정용 냉방기에 널리 사용되고 있는 HCFC22를 대체할 수 있는 혼합냉매의 개발 및 이들의 성능 연구에 관한 것이다. 현재까지 HCFC22를 대체할 수 있는 순수냉매가 없으므로, 혼합냉매 개발에 본 연구의 초점이 맞추어졌고, 이를 위해 가정용 냉방기를 모사 하는 컴퓨터 프로그램이 개발되었다. 연구에서 개발된 혼합냉매를 구성하는 순수냉매들은 다음과 같다: R32, R124, R125, R134, R134a, R143a, R152a. 컴퓨터 모사 결과들은 다음의 혼합냉매들에 대해서 발표되었다: R32/R134a, R32/R152a, R32/R134, R32/R124, R143a/R134a, R143a/R152a, R143a/R124, R125/R134a, R125/R152a, R125/R124, R32/R152a/R134a, R32/R152a/R134, R32/R152a/R124. 가장 좋은 에너지 효율을 보인 것은 삼원 혼합냉매인 R32/R152a/R124로서, HCFC22에 비해 이것의 성적 계수는 13.7% 높고 냉동 능력은 23% 낮은 것으로 판명되었다. 한편 이원 혼합냉매 중 가장 성능이 좋은 것은 R32/R124로서 이것의 성적 계수는 HCFC22에 비해 13.4% 높고 냉동 체적 용량은 9.6% 낮은 것으로 판명되었다.

• 설비공학논문집
• /
• 제24권5호
• /
• pp.391-400
• /
• 2012

In this study, performance of HFC32/HFC152a mixture is measured in the composition range of 20 to 50% R32 with an interval of 10% for the comparison with the conventional HCFC22 in water-source heat pumps. Tests are carried out under the same capacity in a heat pump bench tester equipped with a variable speed compressor at the evaporation and condensation temperatures of 7/$45^{\circ}C$ and -7/$41^{\circ}C$ for summer and winter conditions, respectively. Test results show that the compressor power of the HFC32/HFC152a mixture is 13.7% lower than that of HCFC22 while the coefficient of performance(COP) the HFC32/HFC152a mixture is 15.8% higher than that of HCFC22. Hence, from the view point of energy efficiency, the HFC32/HFC152a mixture is excellent as compared to HCFC22. Compressor discharge temperatures of HFC32/HFC152a mixture are increased up to $15.4^{\circ}C$ as compared to that of HCFC22. The amount of charge for HFC32/HFC152 mixture decrease up to 27% as compared to that of HCFC22. Overall, HFC32/ HFC152a mixture is an excellent long term candidate to replace HCFC22 in water-source heat pumps.

• 설비공학논문집
• /
• 제10권3호
• /
• pp.292-302
• /
• 1998

In this study, 14 refrigerant mixtures composed of R32, R125, R134a, R143a, R152a, and R1270(Propylene) were tested in a breadboard heat pump in an attempt to replace R22 used in most of the residential air conditioners and heat pumps. The heat pump was of 1 ton capacity and water was employed as the secondary heat transfer fluids. All tests were conducted under ARI test A condition. Ternary mixtures composed of R32, R125, and R134a were shown to have 4∼5% higher COP and capacity than R22 and hence they seem to be very promising candidates to replace R22. On the other hand, ternary mixtures containing R125, R134a, and R152a have lower COP and capacity than R22. R32/R134a binary mixtures show a 7% increase in COP and have the similar capacity to that of R22 and hence they are also good candidates to replace R22. Special care must be exercised when a suction line heat exchanger is used with these mixtures in air conditioners. Finally, the compressor discharge temperatures of all mixtures tested were lower than those of R22 by 15.g∼34.7t, which indicates that these mixtures would offer better system reliability and longer life time than R22.

• Journal of Advanced Marine Engineering and Technology
• /
• 제38권4호
• /
• pp.502-507
• /
• 2014

본 논문에서는 혼합작동유체를 해양온도차발전에 적용하였을 때에 그에 따른 사이클의 성능특성에 대해 연구를 수행하였다. 다양한 혼합작동유체 중 본 논문에서는 R32/R152a를 해양온도차발전에 적용하였다. 사이클로는 기존의 밀폐형사이클, 암모니아/물 혼합물에 적용하고 있는 칼리나 사이클에 대해 시뮬레이션 해석을 수행하였고, 온열원의 온도는 $26^{\circ}C$, 냉열원의 온도는 $5^{\circ}C$를 적용하였다. R32를 적용한 밀폐사이클의 출력은 22kW, 사이클의 효율은 2.02%를 보였다. 혼합작동유체를 적용하였을 때에 R32/R152a(90%:10%)의 출력은 29.93kW, 사이클 효율은 2.78%로 기존의 단일 냉매보다 36%, 사이클효율은 37%상승함을 확인 하였다. 칼리나 사이클 또한 위와 같은 방법으로 연구를 수행하였다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제37권8호
• /
• pp.836-842
• /
• 2013

본 연구에서는 고효율 20 kW급 해양온도차 발전사이클을 새롭게 제안하고, 발전사이클의 성능이 최대가 되는 작동유체를 선정하기 위해서 단일냉매 15종과 혼합냉매 16종을 적용하여 발전사이클의 성능을 비교 분석하였다. 시스템 효율, 필요 냉매순환량, 그리고 TPP와 같은 인자를 사용하여 발전사이클의 특성을 분석하였다. 우선, 발전사이클의 효율 측면에서는 R32/R152a(87:13)이 가장 높으며, 필요 냉매 순환량은 R717이 가장 낮다. 그리고 논문에서 새롭게 제시한 TPP의 분석 결과에서는 R32/R134a 70:30이 가장 적합한 냉매로 나타났다. 이상의 결과로부터, 각각의 분석인자에 적합한 냉매는 그 목적에 따라서 다르다는 것을 확인할 수 있었다. 따라서 이러한 분석인자에 맞는 냉매의 선정이 필요하다.

• 설비공학논문집
• /
• 제4권2호
• /
• pp.123-136
• /
• 1992

A preliminary thermodynamic design model of two-evaporator refrigerator/freezer system is constructed. This system is based on Lorentz-Meutzner cycle using refrigerant mixtures. This model screens alternative refrigerant (R32, R125, R143a, R22, R134a, R152a, R124, R142b, R123) mixtures to select the best performance-giving refrigerant mixtures and its composition for the system. Also, it estimates the effects of cooling temperatures of intercoolers, evaporator's area ratio, cooling load ratio on the performance of the system. The COP of the system ranges from 1.4 to 1.6, which is superior to that of the single evaporator system charged with R12 by 13% to 29%. Among 15 mixtures, R22/R123, R143a/R123, R32/R142b, and R32/R124 (in the order of high COP) are most recommendable. For the case of R22/R123, R22 mass fraction more than 0.5(Load Ratio=1.0) or 0.7(Load Ratio=0.33) is recomended in order to replace R12 without reduction in volumetric capacity when keeping the compressor as the same one. COP has the highest value with X(R22)=0.7 and 0.8, respectively. For the case of R143a/R123, in the similar manner, mass fraction of R143a is more than 0.5 or 0.6 while best performance occurs at X(R143a)=0.8. Higher temperature intercooler is more important for the performance of the system than lower temperature intercooler. The area ratio of evaporators is roughly proportional to load ratio of the evaporators.

• 동력기계공학회지
• /
• 제17권6호
• /
• pp.102-107
• /
• 2013

In this paper, the performance analysis for evaporation capacity, total work and efficiency of the ocean thermal energy conversion(OTEC) power system using mixed refrigerant(R32,R152a) is conducted to find the effect of hot wasted water on OTEC power system. The system in this study is applied with two stage turbine, regenerator, cooler and separator on Organic Rankine Cycle. The commercial program HYSYS is used for the performance analysis. The main results were summarized as follows : The efficiency of the OTEC power cycle has a largely effect on the evaporation capacity and total work. As increasing temperature of heat source water, evaporator's capacity is decreased but total work increase. Otherwise, using hot wasted water bring effects not only increasing system efficiency but also declining evaporator's capacity. Thus With a thorough grasp of these effect, it is necessary to find way to use hot wasted water emitted by power plant and so on.