• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.1143-1148
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• 2005

Experimental results for heat transfer characteristic and pressure gradient of HCs refrigerants R-290, R-600a, R-1270 and HCFC refrigerant R-22 during condensing inside horizontal double pipe heat exchangers are presented. The test sections which have one tube diameter of 12.70 mm with 0.86 mm wall thickness, another tube diameter of 9.52 mm with 0.76 mm wall thickness are used for this investigation. The local condensing heat transfer coefficients of hydrocarbon refrigerants were higher than those of R-22. The average condensing heat transfer coefficient increased with the increase of the mass flux. It showed the higher values in hydrocarbon refrigerants than R-22. Hydrocarbon refrigerants have higher pressure drop than those of R-22 in 12.7 mm and 9.52 mm. This results from the investigation can be used in the design of heat transfer exchangers using hydrocarbons as the refrigerant for the air-conditioning systems.

• 대한기계학회논문집B
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• 제21권5호
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• pp.713-723
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• 1997

Performance and heat transfer characteristics of an air conditioning system filled with hydro- carbon refrigerants are experimentally investigated. Single component hydrocarbon refrigerants (propane, isobutane, butane and propylene) and binary mixtures of propane/isobutane and propane/butane are considered as working fluids in the air conditioning system. Performances of each refrigerant are obtained at several compressor speeds and temperature levels of secondary heat transfer fluids. The cooling capacity and the coefficient of performance are obtained as test results. Heat transfer data of selected refrigerants are achieved from overall conductance measurement. Average heat transfer coefficients at different mass fluxes are shown and they are also displayed for different heat capacities of the system. Experimental results show that some hydrocarbon refrigerants have better characteristics than R22.

• 설비공학논문집
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• 제18권3호
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• pp.218-224
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• 2006

The performance of an air to water vapor compression heat pump has been investigated experimentally. The main purpose of this study was to study the possibilities of using hydrocarbon refrigerants as a working fluid to replace R-22 for vapor compression heat pumps. Pure R-22 and R-290, R-600a, R-1270 were considered as working fluids. The performance of the system was characterized by compression shaft work, refrigeration capacity, pressure ratio, discharge temperature and COP. The experimental apparatus has basic parts of cycle that uses the air as a heat source. The experimental results show that refrigeration capacity of HC refrigerants is same or higher than that of R-22. On the other hand, compression shaft work of HC refrigerants is lower than that of R-22. Compression shaft work is lower than that of R-22. Come to the conclusion that, it is possible that hydrocarbon refrigerants could be drop-in alternatives for R-22.

• Journal of Advanced Marine Engineering and Technology
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• 제29권8호
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• pp.870-876
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• 2005

This study of the performance characteristics of natural refrigerants such as R-290 (propane), R-6OOa (iso-butane) and R-1270 (propylene) has investigated to compare with conventional HCFC's refrigerant R-22 for water-cooled heat pump system. The experimental apparatus has basic parts of cycle that uses the water as a heat source. The Performance of the water-cooled system using hydrocarbon refrigerants had been getting better than R-22 from start-up to the similar evaporating temperature after stabilizing system. Through the above it is possible that hydrocarbon refrigerants could be drop-in alternatives for R-22.

• 설비공학논문집
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• 제18권12호
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• pp.1017-1024
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• 2006

In this work, pool boiling heat transfer coefficients (HTCs) of five hydrocarbon refrigerants of propylene, propane, isobutane, butane and dimethylether (DME) were measured at the liquid temperature of $7^{\circ}C$ on a 26 fpi low fin tube, Turbo-B, and Thermoexcel-E tubes. All data were taken from 80 to $10kW/m^2$ in the decreasing order of heat flux. The data of hydrocarbon refrigerants showed a typical trend that nucleate boiling HTCs obtained on enhanced tubes also increase with the vapor pressure. Fluids with lower reduced pressure such as DME, isobutane, and butane took more advantage of the heat transfer enhancement mechanism of enhanced tubes than those enhancement ratios of $2.3\sim9.4$ among the tubes tested due to its sub-channels and re-entrant cavities.

• 설비공학논문집
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• 제18권3호
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• pp.247-253
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• 2006

In this work, pool boiling heat transfer coefficients (HTCs) of hydrocarbon refrigerants are measured from a horizontal smooth tube of 19.0 mm outside diameter. Tested pure refrigerants are Propylene, Propane, Isobutane, Butane and Dimethylether (DME). The pool temperature was maintained at saturation temperature of $7^{\circ}C$ and heat flux was varied from $10kW/m^2$ to $80kW/m^2$ with an interval of $10kW/m^2$. Wall temperatures were measured directly by thermocouple hole of 0.5 mm out-diameter, 152 mm long and inserting ungrounded sheathed thermocouples from the side of the tube. Tested results show that HTCs of Propane, Propylene are 2.5%, 10.4% higher than those of R22 while those of Butane and Isobutane are 55.2%, 44.3% lower than those of R22 respectively. For pure refrigerants, new correlation can be applied to all of CFCs, HCFCS, HFCs, as well as hydrocarbons was developed. The mean deviation was 4.6%.

• 한국산학기술학회논문지
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• 제10권9호
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• pp.2195-2201
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• 2009

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.

• Journal of Advanced Marine Engineering and Technology
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• 제29권5호
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• pp.533-539
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• 2005

Experimental results are presented for heat transfer and pressure gradients of HCs refrigerants R-290, R-600a, R-1270 and HCFC refrigerant R-22 during evaporating inside horizontal double pipe heat exchangers. Two tubes with a tube diameter of 12.70mm and 9.52mm are used for this investigation. Hydrocarbon refrigerants have higher pressure drop than R-22 in 12.7mm and 9.52mm. The results from the investigation can be used in the design of heat transfer exchangers using hydrocarbons as the refrigerant for the air-conditioning systems.

• Journal of Advanced Marine Engineering and Technology
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• 제30권2호
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• pp.218-224
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• 2006

Experimental results for pressure gradient of HCs refrigerants R-290. R-600a. R-1270 and HCFC refrigerant R-22 during condensing inside horizontal double pipe heat exchangers are presented. The test sections which have the tube inner diameter of 10.98mm. and the tube inner diameter of 8mm are used for this investigation. Hydrocarbon refrigerants have higher pressure drop than R-22 in both test sections with the diameters of 12.70mm and 9.52mm. Pressure drop increased with the increase of the mass flux. These results form the investigation can be used in the design of heat transfer exchanger using hydrocarbons as the refrigerant for the air-conditioning systems

• 동력기계공학회지
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• 제12권3호
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• pp.19-25
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• 2008

This paper deals with the heat transfer and pressure drop characteristics of R-290 (Propane), R-600a (Iso-butane) and R-1270 (Propylene) as an environment friendly refrigerant and R-22 as a HCFC's refrigerant for condensing. The test section is a horizontal double pipe heat exchanger. Condensing heat transfer and pressure drop measurements were Peformed for 12.70 mm micro-fin tube and compared with the results in smooth tube. The local condensing heat transfer coefficients of hydrocarbon refrigerants were superior to those of R-22 and the maximum increasing rate of heat transfer coefficient was found in R-600a. The average condensing heat transfer coefficients in hydrocarbon refrigerants showed 20 to 28% higher values than those of R-22. Hydrocarbon refrigerants have a higher pressure drop than that of R-22 with respect to refrigerant qualify and mass flux. Also, the condensing heat transfer coefficient and pressure drop of working fluids in smooth and micro-fin tube were compared. The heat transfer enhancement factor (EF) between smooth and micro-fin tube varied from 2.2 to 2.6 in all experimental conditions.