• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.41-42
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• 2005

The experimental apparatus has been set-up as a conventional vapor compression type heat pump system. The test section is a horizontal double pipe heat exchanger. A tube diameter of 12.70 mm, 9.52 mm, 6.35 mm with 1.78 mm,1.52 mm,1.4 mm wall thickness each is used for this investigation. The local evaporating heat transfer coefficients of hydrocarbon refrigerants were superior to that of R-22. and the maximum increasing rate of heat transfer coefficient was found in R-1270. The average evaporating heat transfer coefficient increased with the increase of the mass velocity and it showed the higher values in hydrocarbon refrigerants than R-22. The highest evaporating heat transfer coefficient of all refrigerants was shown in a tube diameter of 6.35 mm with same mass flux.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.1
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• pp.74-83
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• 2007

This paper presents the experimental results of evaporation heat transfer coefficients of HC refrigerants (e.g. R290 and R600a). R-22 as a HCFCs refrigerant and R-l34a as a HFCs refrigerant in horizontal double pipe heat exchangers, having four different inner diameters of 10.07, 7.73, 6.54 and 5.80 mm respectively. The experiments of the evaporation process were conducted at mass flux of $35.5{\sim}210.4 kg/m^2s$ and cooling capacity of $0.95{\sim}10.1 kW$. The main results were summarized as follows : The average evaporation heat transfer coefficient of hydrocarbon refrigerants(R-290 and R-600a) was higher than the refrigerants, R-22 and R-l34a. In comparison with R-22 the evaporation heat transfer coefficient of R-l34a is approximately $-11{\sim}8.1 %$ higher. R-290 is $56.7{\sim}70.1 %$ higher and R-600a is $46.9{\sim}59.7 %$ higher. respectively. In comparison with experimental data and some correlations, the evaporation heat transfer coefficients are well predicted with the Kandlikar's correlation regardless of a type of refrigerants and tube diameters.

• Solar Energy
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• v.18 no.1
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• pp.69-79
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• 1998

This paper is concerned about the performance of HCFC22 alternative refrigerants used in heat pumps and industrial chillers. A water-to-water breadboard heat pump with counter-current heat exchangers and a hermetic compressor was built to carry out the experiments with various refrigerants. For each test, more than 40 temperatures, 4 pressures, power input, mass flow rates of the heat transfer fluids were measured. Refrigerants tested were HCFC22, R290(Propane), an azeotrope of 45%Propane/55%R134a mixture, and a nonazeotropic mixture of Calor 50. All tests were conducted under ARI test A condition. It is found that the COP and capacity of propane were 18% and 2.5% higher than those of HCFC22 while the COP and capacity of 45%Propane/55%R134a mixture were 3.5% and 5.3% higher than those of HCFC22 respectively. Also the COP and capacity of Calor 50 were 17% and 7.8% higher than those of HCFC22. Compressor discharge temperatures of alternative refrigerants were roughly $35^{\circ}C$ lower than that of HCFC22 indicating that these refrigerants are good from the view point of compressor reliability. The charging amounts for the alternative refrigerants were reduced by 40-60% as compared to that of HCFC22. Overall, it can be said that hydrocarbon containing alternative refrigerants are excellent in thermodynamic performance but should be used with considerable care due to their flammability.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.5
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• pp.754-761
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• 2004

In this paper, evaporating heat transfer characteristics in the refrigeration and air-conditioning facilities were studied using the environmentally friendly refrigerants R-1270 (Propylene). R-290 (Propane). R-600a (Iso-butane) and HCFC refrigerant R-22 The test tube was surrounded by an annulus with water flowing counter to the refrigerant. The tube is copper. with an outside diameter of 12.7mm and the wall thickness of 1.315mm. The test results showed that the local evaporating heat transfer coefficients of hydrocarbon refrigerants were superior to that of R-22 and the maximum increasing rate of heat transfer coefficient was found in R-1270. The average evaporating heat transfer coefficient increased with the increase of the mass velocity and it showed the higher values in hydrocarbon refrigerants than R-22 Comparing the heat transfer coefficient of experimental results with that of other correlations. the presented results had agood agreement with the Kandlikar's correlation. This results form the investigation can be used in the design of heat transfer exchangers using hydrocarbons as the refrigerant for the air-conditioning systems.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.2
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• pp.270-280
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• 1999

A performance analysis simulation program that can be applied to a hermetic reciprocating compressor with various refrigerants has been developed. For the numerical analysis, the passage of refrigerant in compressor is subdivided into control volumes. Instead of the ideal gas assumption, CSD equation of state is applied to calculate the thermodynamic properties of refrigerants. To verify the validity of developed program, the result has been compared with the experimental data served by the compressor supplier. The performance of each refrigerant and the possibility of direct application are estimated by applying R12, 134a, R290, R600a and R290/R600a mixture to an existing compressor. Also, parametric study for various crank rotating speeds and the mole fractions of refrigerant has been performed.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.11a
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• pp.259-264
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• 2003

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.05a
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• pp.191-196
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• 2004

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.05a
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• pp.177-182
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• 2004

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.11a
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• pp.49-55
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• 2004

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.10
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• pp.726-734
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• 2007

In this study, lower flammability limits (LFLs) of three hydrocarbon refrigerants (R600a, R290, R1270) and two hydrofluorocarbon refrigerants (R152a, R32) and DME (RE170) are measured by the method proposed by ASTM E681-04 Standard. Flammability tests are carried out at three temperatures of $23^{\circ}C,\;60^{\circ}C\;and\;100^{\circ}C$ and relative humidity 50%. Test results show that the present data for isobutane and propane obtained at $23^{\circ}C$ are similar to those found in the literature, confirming indirectly the reliability of the present test method and facility. For propylene, R152a, and R32, LFLs found in the literature differ considerably. Especially, the deviation of LFL of propylene is more than 30% among the literature data. The present data for propylene, R152a, and R32 agree with either of the data sets available. As the temperature increases from $23^{\circ}C\;to\;100^{\circ}C$, LFLs of all refrigerants tested decrease. LFLs of most refrigerants tested in this study at $60^{\circ}C$ decrease by $0.1{\sim}0.3%$ as compared to those at $23^{\circ}C$. Also LFLs of most refrigerants tested in this study at $100^{\circ}C$ decrease by $0.1{\sim}0.3%$ as compared to those at $60^{\circ}C$.