• Title/Summary/Keyword: R22 and R134a

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Cycle Simulation of the Air-Conditioner Using Alternatives to R22 (R22의 대체냉매를 사용한 공기조화기의 성능 시뮬레이션)

  • Chang, S.D.;Ro, S.T.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.6 no.1
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    • pp.47-53
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    • 1994
  • Cycle simulation of the air-conditioner was carried out using a number of candidate alternatives to R22;R32/R125/R134a(30/10/60, by mass percent), R32/R125/R134a(10/70/20), R32/R134a(25/75), R32/R134a(30/70), R32/R125(60/40), R290(propane) and R134a. In this study, we considered only the basic parts of the air-conditioner such as the compressor, the evaporator, the condenser and the capillary tube, for the purpose of analysis. The performance characteristics of alternatives considered here were examined by comparing with the case using R22 at the constant volumetric flow rate condition. The results of our analysis revealed that the use of refrigerant mixtures, R32/R134a(30/70) and R32/R125/R134a(30/10/60), was appropriate for the alternatives to R22 in view of the cooling capacity and the COP. For the case of using R134a and R290, the COP was observed to increase under the same volumetric flow rate condition, but the cooling capacity was substantially decreased. Therefore the use of R134a and R290 should be accompanied with increasing considerably the size of compressor in order to maintain the same cooling capacity of R22.

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Computer Simulation Study for Analyzing Alternative Refrigerants in Residential Air-conditioners (가정용 냉방기의 대체 냉매 성능 분석을 위한 전산 해석 연구)

  • Yoo, Hwaan-Kyu;Jung, Dong-Soo
    • Solar Energy
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    • v.15 no.3
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    • pp.75-90
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    • 1995
  • This paper is concerned about alternative refrigerants for HCFC22 used in room air conditioners and heat pumps. Computer simulation of residential air conditioners using refrigerant mixtures is carried out. Following refrigerants are selected as the pure refrigerants constituting the mixtures studied: R32, R124, R125, R134, R134a, R143a and R152a. Simulation results are presented fur the following mixtures: R32/R134a, R32/R152a, R32/R134, R32/R124, R143a/R134a, R143a/R152a, R143a/R124, R125/R134a, R125/R152a, R125/R124, R32/R152a/R134a, R32/R152a/R134, R32/R152a/R124. The best fluid is found to be the ternary mixture of R32/R152a/R124. For that mixture, the coefficient of performance(COP) and volumetric capacity for refrigeration(VCR) are 13.7% larger and 23% smaller than the respective values for HCFC22. R32/R124 mixture is the best binary fluid pair whose COP and VCR are 13.4% larger and 9.6% smaller than those for HCFC22.

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Comparison of Condenser Characteristics using R134a and R22 under the Same Inlet Temperature Condition (동일한 유입온도조건에서 R134a와 R22 적용 응축기의 특성비교)

  • Kang, Shin-Hyung;Byun, Ju-Suk;Kim, Chang-Duk
    • Journal of Energy Engineering
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    • v.15 no.3 s.47
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    • pp.166-173
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    • 2006
  • R134a is considered as an alternative refrigerant to R22 for air conditioners. An experimental investigation was made to study the characteristics of the heat transfer and pressure drop for R134a 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 $60^{\circ}C$ and refrigerant mass fluxes of $150,\;200,\;and\;250\;kg/m^{2}s$. The inlet air has dry bulb temperature or $35^{\circ}C$, relative humidity of 40% and air velocity varying from 0.68 to 1.6 m/s. Experiments show that air velocity decreased by 5.9% is needed for R134a than that of R22 while pressure drop for R134a was $18.1{\sim}20.4%$ higher than that of R22 for the degree of subcooling $5^{\circ}C$. The results are useful in designing more compact and effective condensers for various refrigeration and air conditioning systems using refrigerant R134a.

Performance evaluation of R22 alternative refrigerants (R22 대체냉매의 성능 평가)

  • 송용재;박봉진;정동수;김종보
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.3
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    • pp.292-302
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    • 1998
  • In this study, 14 refrigerant mixtures composed of R32, R125, R134a, R143a, R152a, and R1270(Propylene) were tested in a breadboard heat pump in an attempt to replace R22 used in most of the residential air conditioners and heat pumps. The heat pump was of 1 ton capacity and water was employed as the secondary heat transfer fluids. All tests were conducted under ARI test A condition. Ternary mixtures composed of R32, R125, and R134a were shown to have 4∼5% higher COP and capacity than R22 and hence they seem to be very promising candidates to replace R22. On the other hand, ternary mixtures containing R125, R134a, and R152a have lower COP and capacity than R22. R32/R134a binary mixtures show a 7% increase in COP and have the similar capacity to that of R22 and hence they are also good candidates to replace R22. Special care must be exercised when a suction line heat exchanger is used with these mixtures in air conditioners. Finally, the compressor discharge temperatures of all mixtures tested were lower than those of R22 by 15.g∼34.7t, which indicates that these mixtures would offer better system reliability and longer life time than R22.

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Thermodynamic Properties of Alternatives for R12, R22 and Performances of Refrigerator (R12 및 R22대체냉매의 열역학적 물성치 및 냉동기의 성능비교)

  • Chang, S.D.;Shin, J.Y.;Ro, S.T.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.5 no.1
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    • pp.73-83
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    • 1993
  • Thermodynamic properties of alternatives for R12 and R22 were estimated and performances of refrigerating cycle using these refrigerants were compared. In this study, we adopt R134a, R22/R142b, R22/R152a, R22/R152a/R124 as alternatives for R12 and R32/R134a for R22. Thermodynamic properties of these refrigerants were estimated using modified CSD equation of state. Cycle simulations of the refrigerating system considering heat source were carried out in order to compare the performance of the system. R134a shows relatively lower COP than R12 but very similar VCR. R22/R142b(50/50 mass fraction), R22/R152a(10/90), R22/R152a/R124(30/25/45) are good for the substitutes of R12 and R32/R134a(30/70) is appropriate for that of R22 in view of COP and VCR.

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Condensation Heat Transfer Characteristics of Non-Azeotropic Refrigerant Mixture(NARMs) Inside Double Pipe Heat Exchangers (2중 관형 열교환기내 비공비혼합냉매 R-22+R134a의 응축열전달 특성에 관한 연구)

  • 노건상;오후규;권옥배
    • Journal of Advanced Marine Engineering and Technology
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    • v.20 no.3
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    • pp.91-100
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    • 1996
  • Experimental results for forced convection condensation of non-azeotropic refrigerant mixtures inside a horizontal smooth tube are presented. The mixtures of R-22+R-134a and pure refrigerants R-22 and R-134a are used as the test fluids and a double pipe heat exchanger of 7.5mm ID and 4800mm long inside tube is used. The range of parameters are 100-300kg/h of mass flow rate, 0-1.0 of quality, and 0, 33, 50, 67, and 100 weight percent of R-22 mass fraction in the mixtures. The heat flux, vapor pressure, vapor temperature and tube wall temperature were measured. Using the data, the local and average heat transfer coefficients for the condensation have been obtained. In the same given experimental conditions, the liquid heat transfer coefficients for NARMs were considerally lower than that of the pure refrigerant of R-22 and R-134a. Local heat transfer characteristics for NARMs were different from pure refrigerant R-22 and R-134a. In some regions, local heat transfer coefficients for NARMs were increased in the following order ; Bottom$\rightarrow$Top$\rightarrow$Side. The condensation heat transfer coefficients for NARMs increased with mass velocity, heat flux, and quality, but were considerably lower than that of pure refigerant R-22 and R-134a.

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Drop-In Evaluation of Thermodynamic Performance of R-22 Alternative Refrigerant Mixtures (R-22 대체용 혼합냉매의 Drop-In 열역학적 성능 계산)

  • Ju, J.M.;Kim, C.N.;Park, Y.M.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.8 no.3
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    • pp.423-436
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    • 1996
  • Thermodynamic performance of eight zeotropic R-22 alternative refrigerant mixtures selected by AREP(R-22 Alternative Refrigerants Evaluation Program) and R-32/R-125/R-134a(23%/25%/52%), namely R-407C were evaluated by the "drop-in" simulation method. An existing air conditioner was selected and its design data were used for the simulation. "ARI Test A" air conditions were applied. The degree of vapor superheat at the compressor inlet fixed at $5^{\circ}C$ for all the mixtures. The results of the simulation were compared with those of R-22. COPs of all mixtures except for R-32/R-227ea(35%/65%) and R-32/R-125/R-134a(10%/70%/20%), were higher than that of R-22 by 2%~8%, while the capacities were all lower than that of R-22 by 13%~27%. COP of R-32/R-134a(40%/60%) was 2.4% higher but the capacity was 15% lower than those of R-22. In the case of R-32/R-134a(30%/70%), COP and capacity were 5.5% higher and 15% lower than those of R-22, respectively. Among the ternary mixtures, R-407C and R-32/R-125/R-134a(30%/10%/60%) showed the best performance. COP of R-407C was 2.4% higher than those of R-22 but the capacity was 15% lower.

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External Condensation Heat Transfer Coefficients of R22 Alternative Refrigerants and R134a According to the Saturated Vapor Temperature Change on a Smooth Tube (수평관에서 R22 대체냉매 및 R134a의 포화증기 온도변화에 따른 외부 응축 열전달계수에 관한 연구)

  • Yoo Gil-Sang;Hwang Ji-Hwan;Park Ki-Jung;Jung Dongsoo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.8
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    • pp.729-735
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    • 2005
  • In this study, external condensation heat transfer coefficients (HTCs) were measured on a horizontal smooth tube at the saturated vapor temperature of $30^{\circ}C,\;39{\circ}C,\;and\;50^{\circ}C$ for R22, R410A, R407C, and R134a with the wall subcooling of $3\~8^{\circ}C$. The HTCs of all refrigerants are the highest at $30^{\circ}C,\;39{\circ}C,\;and\;50^{\circ}C$ in order. This trend is due to its excellent thermodynamic properties of the liquid phase. The measured data of HTCs were compared with the calculated ones by Nusselt's equation for a smooth tube. Measured HTCs of R22, R134a, R410A are $4.2\~7.5\%$ higher than prediction respectively while those of R407C are $15.6\~28.9\%$ lower than the prediction.

A Performance Comparison of Oil-free Scroll Compressors with R-12, R-134a and R-22 (R-12, R-134a 및 R-22를 사용한 무급유식 스크롤압축기의 성능 비교)

  • Pak, H.Y.;Park, K.W.;Park, Y.I.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.5 no.4
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    • pp.306-317
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    • 1993
  • In this study, a performance comparison of scroll compressor for various refrigerants(CFC-12, HCFC-22 and HFC-134a) has been numerically carried out. The thermodynamic properties have been calculated by using the recent experimental equations and the performance has been investigated qualitatively at the same geometric specifications and operating conditions of scroll compressor. The results are as follows; HFC-134a has the highest compression ratio of 5.40. The mass flow rate of HCFC-22, which affects the cooling capacity of refrigerant system, is higher than that of other refrigerants. HFC-134a has the highest adiabatic efficiency in comparison with CFC-12 and HCFC-22.

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Evaporation Heat Transfer Characteristics of R-22, R-134a in Small Diameter Tubes (세관내 R-22, R-134a의 증발 전열 특성에 관한 연구)

  • 홍진우;박승준;오종택;오후규
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.12
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    • pp.1081-1089
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    • 2000
  • Evaporating heat transfer coefficients of R-22 and R-134a were measured in smooth horizontal copper tubes with inner diameters of 1.77, 3.36 and 5.35mm, respectively. The experiments were conducted in a closed loop, which was driven by a magnetic gear pump. Experiments were performed for the following range of variables: mass velocity (200 to 400 kg/$m^2$.s), saturation temperature($0^{circ}C,; 5^{\circ}C$) and quality(0 to 1.0). Main results obtained are as follows: evaporating heat transfer coefficients in the small diameter tubes (ID<7mm) were observed to be strongly affected by various diameters and to differ from those in the large diameter tubers. The heat transfer coefficients of the small diameter tubes were higher than those of the large diameter tubs. And it was very difficult to apply some well-known previous predictions (Shah`s, Gungor-Winterton`s and Kandlikar`s correlation) to small diameter tubes.

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