• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.20 no.3
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• pp.205-214
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• 1991

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.20 no.3
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• pp.215-217
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• 1991

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.21 no.3
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• pp.202-215
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• 1992

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.21 no.3
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• pp.221-235
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• 1992

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.21 no.3
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• pp.166-173
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• 1992

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.21 no.3
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• pp.174-188
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• 1992

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.21 no.3
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• pp.189-201
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• 1992

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.9
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• pp.2358-2372
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• 1993

In this study, the computer modeling for prediction of the performance of fin-tube heat exchanger using alternative refrigerant, HFC-134a was developed and the computer program for calculating the various properties of HFC-134a and the existing refrigerant CFC-12 and HCFC-22 was made. The heat exchanger modeling is based on a tube-by-tube approach, which is capable of analysis for the complex coil array. Performance of each tube is analyzed separately by considering the cross-flow heat transfer with external airstream and the appropriate heat and mass transfer relationships. A performance comparison according to the different refrigerants is provided using this developed model. As the result of this study, total heat transfer rate of evaporator and condenser using HFC-134a were found higher than that of using CFC-12 for the same operating conditions. When the mass flow rate of HFC-134a was less than CFC-12 about 18. 16%, the cooling capacities of evaporator were found to be the same.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.3
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• pp.366-381
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• 1995

A performance analysis of refrigeration system using the HFC-134a and scroll compressor is performed numerically. The refrigeration system mainly consists of various standard components such as heat exchanger, compressor, and expansion device. The model for heat exchanger performance is based on a tube-by-tube method which is analyzed separately by considering the cross-flow heat transfer with the outdoor air flow and pressure drop. Compressor is used the scroll-type compressor which has many merits such as high efficiency, low noise and vibration, and small in size. Short-tube is included as an expansion device. Vapour and liquid line are also considered for the performance analysis of refrigeration system. Using the modeling of various components of refrigeration system, a performance comparison of CFC-12 and HFC-134a is performed numerically for the various outdoor air temperature and various values of short-tube diameter. As the results of this study, the refrigeration system performance decreases as the outdoor air temperature increases. And the optimum short-tube diameter based on COP is 1.37mm for this system.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.247-248
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• 2002

CFCs는 가정제품과 공업의 생산과정에서 발포제와 냉매제로 오랜 기간 사용되었다. 1974년, CFCs는 Molina와 Rowland에 의해서 성층권 오존의 고갈 요인으로 인식하게 되었고, 최근에는 지구 온난화의 기여물질로써 사회적 관심이 증가하였다. CFCs의 세계적인 생산은 Montreal 의정서와 그 개정안으로 인해 점차 감소하면서 사용이 폐지되었고, 대체 물질로 HCFCS와 HFCs가 사용되고 있다. 대류권에서 HCFCs와 HFCs는 hydroxyl radicals에 의해 산화되고, 최종 분해산물로 무기산, 염, HF, $CO_2$, HC와 Trifluoroacetic acid(TFA)가 생성된다. (중략)