• Polymer Science and Technology
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• v.2 no.2
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• pp.99-104
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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.161-165
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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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• 2001.11a
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• pp.331-332
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• 2001

CFCs는 가정 제품과 공업적 과정에서 발포제와 냉매제로 오랜 기간 사용되었다. 1974년, CFCs는 Molina와 Rowland에 의해 성층권 오존의 고갈 요인으로 인식되었고, 최근에는 지구 온난화의 기여물질로써 관련되어 지고 있다. CFCs의 세계적인 생산은 Montreal 의정서와 그 개정안에 의해 점차 폐지되었고, 대체 물질로 HCFCs와 HFCs가 과도하게 사용되고 있다. 수소의 존재는 대체 물질의 대류권 산화를 가능하게 했고, 대체로 성층권에 영향을 미치지 않는다. (중략)

• 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)

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.3
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• pp.413-420
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• 2018

This paper documents the result of a preliminary analysis on the influence of hull-ice friction coefficient on model resistance and power predictions and their correlation to full-scale measurements. The study is based on previous model-scale/full-scale correlations performed on the National Research Council - Ocean, Coastal, and River Engineering Research Center's (NRC/OCRE-RC) model test data. There are two objectives for the current study: (1) to validate NRC/OCRE-RC's modeling standards in regarding to its practice of specifying a CFC (Correlation Friction Coefficient) of 0.05 for all its ship models; and (2) to develop a correction methodology for its resistance and propulsion predictions when the model is prepared with an ice friction coefficient slightly deviated from the CFC of 0.05. The mean CFC of 0.056 and 0.050 for perfect correlation as computed from the resistance and power analysis, respectively, have justified NRC/OCRE-RC's selection of 0.05 for the CFC of all its models. Furthermore, a procedure for minor friction corrections is developed.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.2
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• pp.131-136
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• 1995

The experiment for decomposing CFF-113 by a honeycomb catalyst was carried out in this study. Benzene and water were used as decomposing agents. The reaction of decomposition was from 600 .deg.C to 900.deg.C. Benzene was injected at 900.deg.C and then the catalyst was heated to 1100.deg.C by the heat of combustion of it. The electric power of the reactor was turned off when the combustion was started. The reaction temperature, however, was main trained and the decomposition of CFC-113 continued at that time. It was found that the highest decomposition efficiency was 80% at the ratio of benzene/CFC-113 of 20/1 in this experiment.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.534-541
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• 1997

Isothermal solubilities of nitrogen in clean fire extinguishing agents, such as bromotrifluoromethane (Halon-1301), bromochlorodifluoromethane (Halon-121 t), 1,1,1,2,3,3,3- heptafluoropropane (HFC-227ea), and trifluoroiodomethane (FIC-13I1) were measured in a circulation-type equilibrium apparatus. The temperature range was (293.2 to 313.2) K and the pressure range was (30 to 100) bar. The experimental data were well correlated with the Peng- Robinson equation of state using the Wong and Sandier mixing rules, and the relevant parameters are presented.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.2
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• pp.23-35
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• 1993

1. 몬트리올 의정서. 2. 우리나라 오존층보호 규제. 3. 특정물질 사용감축 방안. 4. 우리나라 자동차업계의 대체냉매 에어컨 개발동향