• 설비공학논문집
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• 제14권1호
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• pp.73-82
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• 2002

A small refrigeration system used in a water purifier was tested by employing propane/isobutane (R-290/R-6OOa) mixtures as an alternative refrigerant of R-12. The drop-in tests were performed by varying mass fraction of propane at 0.25, 0.5 and 0.75 with a change of both refrigerant charge amount and capillary tube length in order to find an optimum composition in aspect of performance and reliability of the system. As a result, the mixture of 50% propane-50% isobutane showed the best performance and reliability among them in a small refrigeration system. During steady state operations, both the COP and refrigeration capacity increased by 4% and 9%, respectively, as compared to the baseline R-12 system. In addition, the propane/isobutane (50/50) mixture system yielded advantages in the minimization of modification and redesigning of system components due to very similar saturation tempera- ture and pressure characteristics with R-12.

• Journal of Mechanical Science and Technology
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• 제20권3호
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• pp.399-408
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• 2006

Nucleate pool boiling heat transfer coefficient (HTCs) were measured with one nonazeotropic mixture of propane/isobutane and two azeotropic mixtures of HFC134a/isobutane and propane/HFC 134a. All data were taken at the liquid pool temperature of $7^{\circ}C$ on a horizontal plain tube of 19.0mm outside diameter with heat fluxes of $10\;kW/m^2\;to\;80kW/m^2$ with an interval of $10\;kW/m^2$ in the decreasing order of heat flux. The measurements were made through electrical heating by a cartridge heater. The nonazeotropic mixture of propane/isobutane showed a reduction of HTCs as much as 41% from the ideal values. The azeotropic mixtures of HFC134a/isobutane and propane/HFC134a showed a reduction of HTCs as much as 44% from the ideal values at compositions other than azeotropic compositions. At azeotropic compositions, however, the HTCs were even higher than the ideal values due to the increase in the vapor pressure. For all mixtures, the reduction in heat transfer was greater with larger gliding temperature difference. Stephan and Korner's and lung et al's correlations predicted the HTCs of mixtures with a mean deviation of 11%. The largest mean deviation occurred at the azeotropic compositions of HFC134a/isobutane and propane/HFC134a.

• 설비공학논문집
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• 제18권12호
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• pp.955-963
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• 2006

Nucleate pool boiling heat transfer coefficients (HTCs) were measured with one nonazeotropic mixture of Propane/Isobutane and two azeotropic mixtures of HFC134a/Isobutane and Propane/HFC134a. All data were taken at the liquid pool temperature of $7^{\circ}C$ on a horizontal plain tube with heat fluxes of $10kW/m^2\;to\;80kW/m^2$ with an interval of $10kW/m^2$ in the decreasing order of heat flux. The measurements were made through electrical heating by a cartridge heater. The nonazeotropic mixture of Propane/Isobutane showed a reduction of HTCs as much as 41% from the ideal values. The azeotropic mixtures of HFC134a/Isobutane and Propane/HFC134a showed a reduction of HTCs as much as 44% from the ideal values at compositions other than azeotropic compositions. At azeotropic compositions, however, the HTCs were even higher than the ideal values due to the increase in the vapor pressure. For all mixtures, the reduction in heat transfer was greater with a larger gliding temperature difference. Stephan and $K{\ddot{o}}rner's$ and Jung et al's correlations predicted the HTCs of mixtures with a mean deviation of 11%. The largest mean deviation occurred at the azeotropic compositions of HFC134a/Isobutane and Propane/HFC134a.

• 대한기계학회논문집B
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• 제29권2호
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• pp.271-278
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• 2005

In this paper, the performance of Kim-chi refrigerator with three evaporator and one compressor was investigated in employing $55\%$ propane and $45\%$ isobutane (R290/R600a) refrigerant mixture as an alternative refrigerant of R134a. The drop-in test was performed by varying both refrigerant charge and capillary tube length in order to find both the performance and reliability of a small multi-refrigeration system. Results show that the power consumption is decreased by about $15\%$ and COP is increased by about $10\%$, respectively as compared to the baseline system using R-134a. In addition, the propane/isobutane refrigerant mixture system took advantage of the minimization of modification and redesigning of system components because thermodynamic properties such as saturation pressure, temperature, normal boiling point(NBP) characteristics are similar to those of R134a. The reduction of sales cost is caused by the decrease of refrigerant cost per unit mass and refrigerant charge amount necessary for the refrigeration system.

• 대한기계학회논문집B
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• 제21권12호
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• pp.1656-1667
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• 1997

Condensing heat transfer characteristics of hydrocarbon 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 test fluids. Local condensing heat transfer coefficients of selected refrigerants are obtained from overall conductance measurement. Average heat transfer coefficients at different mass fluxes and heat transfer rates are shown and compared with those of R22. Pure hydrocarbon refrigerants have higher values of heat transfer coefficient than R22. It is also found that there is a heat transfer degradation for hydrocarbon mixtures due to composition variation during condensation. Measured condensing heat transfer coefficients are compared with predicted values by available correlations. An empirical correlation for pure and mixed hydrocarbon is developed, and it shows good agreement with experimental data.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1945-1950
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• 2004

In this paper, The performance of Kim-Chi refrigerator with three evaporator and one compressor was investigated in employing 55% propane and 45% isobutane (R290/R600a) refrigerant mixture as an alternative refrigerant of R134a. The drop in test was performed by varying both refrigerant charge amount and capillary tube length in order to find both the performance and reliability of a small multi-refrigeration system. As a result, Both the power consumption and COP is increased by about 15% and 10%, respectively as compared to the baseline R134a system. In addition, the propane/isobutene refrigerant mixture system took advantage of the minimization of modification and redesigning of system components because of similar thermodynamic properties with R134a such as saturation pressure, temperature, normal boiling point(NBP) characteristics

• 설비공학논문집
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• 제7권2호
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• pp.249-265
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• 1995

The performance of a refrigerant mixture of propane(R290)/isobutane(R600a) as a substitute for CFC12 was investigated in a domestic refrigerator with single evaporator. A thermodynamic cycle simulation indicated an increase in COP of a 1.7 to 2.4% with R-290/600a in the composition range of 0.2 to 0.6 mass fraction of R290 compared to CFC12. For the tests, two units($299{\ell}$, $465{\ell}$) were used. All refrigeration components remained the same throughout the tests, except that the length of capillary tube and amount of charge were changed for the mixture. The refrigerators were fully instrumented with more than 20 thermocouples, 2 pressure transducers, and watt/watt-hour meter for each refrigerator. 'Energy consumption test' and 'no load pulldown test' were performed under the same condition. The experimental results obtained with the same compressor indicated that R-290/600a mixture at 0.6 mass fraction of R290 showed a 3 to 5% increase in energy efficiency and a faster cooling speed compared to CFC12. The R-290/600a mixture showed a shorter compressor on-time and a lower compressor dome temperature than CFC12. In conclusion, the proposed hydrocarbon mixture seems to be an appropriate candidate to replace CFC12 without causing more environmental problems.

• 설비공학논문집
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• 제10권6호
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• pp.683-694
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• 1998

The application of hydrocarbon refrigerants in a hermetic reciprocating compressor for refrigerator is investigated. The selected refrigerants are isobutane(R600a), propane(R290), R12, binary mixture of R600a/R290, and OS-21CII. Both theoretical and experimental investigations have been performed for the selected refrigerants. The test results of hydrocarbon refrigerants have been compared to the traditional refrigerant(R12). The results show that hydrocarbon refrigerants(HC-Blend, OS-21C II) are very good alternatives in the refrigeration system for R12.

• 대한화학회지
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• 제7권2호
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• pp.128-132
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• 1963

A study has been made on the applicability of gas-liquid partition chromatography to the qualitative and quantitative analysis of complex mixture of gaseous hydrocarbons. While phthalate columns are widely used for this $purpose^9$, they separates neither saturated hydrocarbons from the unsaturated nor n-butane from isobutene or butene-1, therefore combined columns such as phthalate and dimethylsulfolane have been used for the perfect separation of gaseous hydrocarbons. It is shown by this study, however, that hydrocarbons having $C_1$ through $C_4$ can be separated with a 2-meters tetraethyleneglycol dimethylether column except ethane from ethylene, and trans-from cis-2-butene especially operated at $15^{\circ}C$$ using helium as the carrier gas. The column effluents were in order of methane, (ethane, ethylene), propane, propylene, isobutane, n-butane, isobutylene, butene-1, (trans-& cis-2-butene, isopentane), (butadiene-1, 3, n-pentane). Two kinds of liquified petroleum gases in market are analysed qualitatively and quantitatively. The results indicate that use of this 2-meters TEGDE column permits the separation and identification of all the commonly encountered aliphatic gaseous hydrocarbons.