• Title/Summary/Keyword: R-407A

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Evaporation Heat Transfer and Pressure Drop of Mixture Refrigerant R-407C (혼합냉매 R-407C의 증발 열전달과 압력강하)

  • Roh, Geon-Sang;Oh, Hoo-Kyu;Son, Chang-Hyo
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.4
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    • pp.542-549
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    • 2008
  • The evaporation heat transfer coefficient and pressure drop of R-22 and R-407C in a horizontal copper tube were investigated experimentally. The main components of the refrigerant loop are a receiver, a compressor, a mass flow meter, a condenser and a double pipe type evaporator (test section). The test section consists of a smooth copper tube of 6.4 mm inner diameter. The refrigerant mass fluxes were varied from 100 to $300\;kg/m^2s$ and the saturation temperature of evaporator were $5^{\circ}C$. The evaporation heat transfer coefficients of R-22 and R-407C increase with the increase of mass flux and vapor quality. The evaporation heat transfer coefficients of R-22 is about $5.68{\times}46.6%$ higher than that of R-407C. The evaporation pressure drop of R-22 and R-407C increase with the increase of mass flux. The pressure drop of R-22 is similar to that of R-407C. In comparison with test results and existing correlations, correlations failed to predict the evaporation heat transfer coefficient of R-22 and R-407C. therefore, it is necessary to develope reliable and accurate predictions determining the evaporation heat transfer coefficient of R-22 and R-407C in a horizontal tube.

An experimental study on nucleate boiling of ternary refrigerant R407C (삼중 혼합 냉매 R407C의 핵비등 열전달 특성에 관한 실험적 연구)

  • Kim, S.H.;Kwak, K.M.;Bai, C.H.;Chung, M.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.9 no.3
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    • pp.276-283
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    • 1997
  • The nucleate boiling heat transfer experiments are performed using a ternary refrigerant R407C which is a candidate of alternatives of HCFC 22. The boiling phenomena for R-32, R-125, and R-134a which are the constituent refrigerants of R407C are also investigated to give the foundation of theoretical research for the mixture component boiling. The nucleate boiling heat transfer coefficients of R407C is less than those of HCFC 22 which has the similar physical and transport properties. Since the experimental results show the deterioration of boiling heat transfer coefficients of ternary mixture refrigerants R407C, the boiling heat transfer coefficients of R407C cannot be obtained by the linear combination of boiling heat transfer coefficients from its constituent components R-32, R125, and R134a.

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Study on the pressure drop of ternary refrigerant R-407c during condensation inside horizontal micro-fin tubes (3성분 혼합냉매 R-407c의 수평 마이크로핀관내 응축압력강하에 관한 연구)

  • 정재천
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.2
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    • pp.210-218
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    • 1998
  • Experimental results for forced convection condensationof Refrigerant-22 and ternary Refrigerant-407c(HFC-32/125/134a 23/25/52 wt%) considered as a substitute R-22 inside horizontal micor-fin tubes are presented. The test section was horizontal double-tubed counterflow condenser with a length 4000 mm micro-fin tube having 9.53 mm OD., 0.2 mm fin height and 60 fins. The refrigerants R-22 and R-407c were cooled by a coolant circulated in a surrounding annulus. The range of parameters of mass velocity was varied from 102.1 to 301.0kg/($\textrm{m}^{2}.s$) with inlet quality 1.0. Both refrigerant R-22 and its alternative refrigerant R-407c were tested within the same range of parameters. At the given experimental conditions for R-22 and R-407c the pressure drops for R-407c were considerably higher than those for R-22 at micro-fin tubes. Over the mass velocity range tested the PF(penalty factor)was lower than the increasing ratio of heat transfer area by fins. Based on the data correlation was proposed for predicting the frictional pressure drops for R-22 and R-407c for a duration of condensation inside a horizontal micro-fin tube.

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Comparison of Condenser Characteristics Using R407C and R22 on the Same Inlet Temperature Condition (동일한 유입온도조건에서 R407C와 R22 적용 응축기의 특성비교)

  • 김창덕;전창덕;이진호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.7
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    • pp.595-603
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    • 2003
  • R407C is considered as an alternative refrigerant to R22 for air conditioners. An experimental investigation was made to study the characteristics of the condensation heat transfer and pressure drop for R407C flowing in a fin-and-tube heat exchanger used for commercial air-conditioning units. Experiments were carried out under the conditions of inlet refrigerant temperature of 6$0^{\circ}C$ and refrigerant mass flux varying from 150 to 250 kg/$m^2$s for refrigerant side. The inlet air has dry bulb temperature of 35$^{\circ}C$ , relative humidity of 50% and air velocity varying from 0.8 to 1.6 m/s. Experiments show that air velocity increased by 25% is needed for R407C than that of R22 for subcooling temperature of 5$^{\circ}C$, which resulted in air-side pressure drop increase of 28.8% for R407C as compared to R22. As a consequence, in order to provide the same design condition of a condenser, the fan requires higher electric-power consumption with R407C than that with R22.

Evaporation Heat Transfer and Pressure Drop of Mixture Refrigerant R-22 and R-407C in a Diameter of 4.3 mm (4.3 mm 세관내 R-22와 R-407C의 증발 열전달과 압력강하)

  • Roh, G.S.;Son, C.H.
    • Journal of Power System Engineering
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    • v.12 no.4
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    • pp.26-31
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    • 2008
  • The evaporation heat transfer coefficient and pressure drop of R-22 and R-407C in a small diameter copper tube were investigated experimentally. The main components of the refrigerant loop are a receiver, a compressor, a mass flow mete, a condense and a double pipe type evaporate (test section). The test section consists of a smooth copper tube of 4.3 mm inner diameter. The refrigerant mass fluxes were varied from 100 to $300[kg/m^{2}s]$ and the saturation temperature of evaporator were $5[^{\circ}C]$. The evaporation heat transfer coefficients of R-22 and R-407C increase with the Increase in mass flux and vapor quality. The evaporation heat transfer coefficient of R-22 is about $7.3\sim47.1%$ higher than that of R-407C. The evaporation pressure drop of R-22 and R-407C increase with the increase of mass flux. The pressure drop of R-22 is about $8\sim20%$ higher than that of R-407C.

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Investigation on the selection of capillary tube for the alternative refrigerant R-407C (대체냉매 R-407C의 모세관 선정에 관한 연구)

  • 김용환;김창년;박영무
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.1
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    • pp.56-65
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    • 1998
  • In this paper, experimental investigation of capillary tube performance for R-407C is performed. The experimental setup is made of real vapor-compression refrigerating system. In this study, mass flow rate is measured for capillary tubes of various diameter and length as inlet pressure and degree of subcooling are changed. These data are compared with the results of a numerical model. The mass flow rates of the numerical model are less than by 14% compared with the measured mass flow rates. It is found that mass flow rate and length for R-407c are less than those of R-22 under the same condition. Also based on this experimental study and the numerical model, a set of capillary tube selection charts for R-407C is constructed.

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Prediction of Nucleate Pool Boiling Heat Transfer Coefficients of Ternary Refrigerant R407C

  • Kwak, Kyung-Min;Bai, Cheol-Ho;Chung, Mo
    • International Journal of Air-Conditioning and Refrigeration
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    • v.6
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    • pp.93-103
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    • 1998
  • The nucleate boiling heat transfer experiments are performed using a ternary refrigerant R407C which is a candidate of alternatives of HCFC 22. The boiling phenomena of R-32, R-125 and R-134a which are the constituent refrigerants of R407C are also investigated. The nucleate boiling heat transfer coefficients of R407C are less than those of HCFC 22 which have the similar physical and transport properties. In our experimental pressure range, which is similar to the operational pressure of air conditioning system, the deterioration of boiling heat transfer coefficients of mixture refrigerant R407C does not appear for moderate wall superheat region. Since nucleate boiling heat transfer coefficients cannot be obtained from ideal mixing law of mixture, Thome's method was used to predict. To account for the heat flux effect and system pressure in Thome's method, the correcting factor, a(P.L1T), was introduced and obtained from experiments for ternary refrigerant R407C.

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A study on prediction of oil concentration in the R-407C and R-410A refrigeration system (대체냉매 R-407C와 R-410A를 사용하는 냉동시스템의 오일농도 예측에 관한 연구)

  • 이종문;김창년;박영무
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.3
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    • pp.384-390
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    • 1999
  • A vibrating U-Tube decimeter has been evaluated as a sensor for measuring the concentration of oil in the liquid line of a refrigeration system. Calibration and performance tests were conducted under simulated liquid-line conditions for R-407C/POE oil and R-410A/POE oil mixtures in oil concentration from 0 to 15 weight percent. Test temperatures ranged from 20 to 5$0^{\circ}C$. As a result of test, oil concentration correlations are presented in terms of specific gravity at each constant temperature. These equations enable to predict the oil concentration without any extraction of the mixture, and can be applied for R-407C/POE oil and R-410A/POE oil mixtures.

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Effects of the Temperature Glide and Superheat of R407C on the Performance of Evaporator (R407C의 온도구배와 과열도가 증발기 성능에 미치는 영향)

  • 김창덕;전창덕;이진호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.10
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    • pp.852-859
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    • 2003
  • R407C is considered as an alternative refrigerant of R22 for air conditioners. An experiment was carried out to investigate the characteristics of the evaporation heat transfer and pressure drop for refrigerant R407C flowing in a fin-and-tube heat exchanger used for commercial air-conditioning unit. The experimental data were useful in analyze the effects of the temperature glide and superheat for R407C. Test were conducted at the conditions of inlet refrigerant evaporation temperature of 7$^{\circ}C$, inlet air relative humidity of 50%, and refrigerant mass fluxes varying from 150 to 250 kg/m$^2$s. Representative results show that the heat exchanger performance for R407C evaporation is significantly affected by the change of the flow pattern from two-phase to super-heated vapor flow.

Experimental Study for Evaporation Heat Transfer and Pressure Drop of R-22 and R-407C in an Inner Diameter of 4.3 mm and 6.4 mm (내경 4.3 mm와 6.4 mm관내 R-22와 R-407C의 증발 열전달과 압력강하에 관한 실험연구)

  • Son, Chang-Hyo;Roh, Geon-Sang
    • Journal of the Korean Institute of Gas
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    • v.12 no.3
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    • pp.43-49
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    • 2008
  • The evaporation heat transfer coefficient and pressure drop of R-22 and R-407C in horizontal copper tubes were investigated experimentally. The main components of therefrigerant loop are a receiver, a compressor, a mass flow meter, a condenser and a double pipe type evaporator (test section). The test section consists of a smooth copper tube of 4.3 mm and 6.4 mm inner diameter. The refrigerant mass fluxes were varied from 100 to $300[kg/m^2s]$ and the saturation temperature of evaporator were 5 [$^{\circ}C$]. The evaporation heat transfer coefficients of R-22 and R-407C rise with the increase in mass flux and vapor quality. The evaporation heat transfer coefficient of R-22 for inner diameter tube of 4.3 mm and 6.4 mm is about $7.3{\sim}47.1%$ and $5.68{\sim}46.6%$ higher than that of R-407C, respectively.

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