• Title/Summary/Keyword: Refrigerating efficiency

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Study on the Performance of the Cascade System Using Alternative Refrigerants (대체냉매를 사용한 이원냉동 시스템의 성능에 관한 연구)

  • 박종훈;조금남
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.7
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    • pp.564-571
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    • 2001

  • The present study investigated the effect of key parameters on the performance of a cascade system using R-22 and R-23 refrigerants. Experimental data for the cascade system have been compared with simulation results using thermodynamic analysis. The cascade system tested at the evaporating temperature of $-80^{\circ}C $ and the condensing temperature of$40^{\circ}C $. The key experimental parameters were the evaporating temperature of the HTC(-35, -30, -25, -20, $-15^{\circ}C $) and mass flux of the HTC(200, 250, 300kg/$m^2$s). As the evaporating temperature and the mass flux of the HTC were increased respectively, the COP and the refrigerating efficiency were increased and then decreased while the volume flow rate per unit refrigeration capacity showed the opposite trend. The maximum COP and refrigerating efficiency were obtained at the evaporating temperature of the HTC of $-25^{\circ}C $ and the mass flux of 250 kg/$m^2$s.

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An Experimental Study on the Thermal Efficiency of the Ondol House Beating System (온돌의 열효율에 관한 실험적 연구)

  • Bae soonhoon;Kang Shin-Hyoung
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.4 no.3
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    • pp.183-190
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    • 1975

  • Most Korean houses are heated by the Ondol heating system. There has been, however, no reasonable design procedure availabe yet for the system. The conventional design should be improved to have auniform floor surface. temperature distribution and to have a high thermal efficiency. Thermal efficiencies of the ondol were defined and the method of experimentation was studied. An experiment, using a life-size model which was well insulated, was performed to observe the variation in thermal efficiency as the length of fuel burning time was varied.

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