• Title/Summary/Keyword: Refrigerant R-22

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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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A Study on the Dynamic Characteristics of Nitrogen Mixed Gas for Thermostatic Expansion Valve Sensing Blub (온도 감지식 팽창밸브 감온통 질소가스 혼합냉매의 동특성 연구)

  • Kim, Si-Young;Koo, Su-Jin;Ju, Chang-Sik
    • Journal of Power System Engineering
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    • v.18 no.1
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    • pp.69-75
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    • 2014
  • The pressure and temperature characteristics of mixed refrigerant gases in bulb for thermostatic expansion valve were studied using R22 refrigerant and $N_2$ gases. The characteristics of mixed refrigerant gases were investigated according to pressure variation and the variation of composition ratio of R22 refrigerant and $N_2$ gases in the temperature range of -$15^{\circ}C$~$15^{\circ}C$. The Maximum operating pressure(MOP) of mixed refrigerant gases were showed a tendency to decrease with decreasing the mixing ratio of $N_2$ gas. The characteristics in the case of the mixing ratio of 90:1 for R22 refrigerant and $N_2$ gases were the same result as Reference refrigerant. In addition, the characteristics of the mixed refrigerant gases in the mixing ratio of 90:1 for R22 refrigerant and $N_2$ gases were showed almost linear in the measurement range of pressure-temperature, and the physical properties also were showed similar results with Reference refrigerant. It was able to confirm that a MOP on the thermostatic expansion valve for sensing bulb can be maintained by adjusting the mixing ratio of R22 refrigerant and $N_2$ gases.

Performance Analysis of a Heat Pump Using Refrigerant Mixtures (II) (혼합냉매를 사용한 열펌프의 성능해석 (II))

  • Kim, M.S.;Kim, T.S.;Won, S.P.;Ro, S.T.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.2 no.3
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    • pp.218-225
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    • 1990
  • Studies on the performance of a heat pump using non-azeotropic refrigerant mixtures are done. In order to estimate the thermodynamic properties for the selected non-azeotropic refrigerant mixtures including R22/R152a, R22/R142b, R22/R114 and R13B1/R152a, Peng-Robinson equation of state is adopted. The pressure-enthalpy diagram and the temperature-entropy diagram are plotted for each refrigerant mixture. Considerations on the capacity modulation for the heat pump system using refrigerant mixtures are taken into. Results show that when the heating load varies, the possibility for the capacity modulation is found in the heat pump system using a compressor with constant volume flow rate. Under a constant heating capacity condition in the heat pump system, the coefficient of performance increases when the refrigerant mixtures are used. The volume flow rate decreases as the mass fraction of lower boiler increases in this case.

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Comparison of Condenser Characteristics using R410A and R22 under the Same Inlet Temperature Condition (동일한 유입온도조건에서 R410A와 R22 적용 응축기의 특성비교)

  • 김창덕;이진호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.12
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    • pp.1049-1059
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    • 2003
  • R410A 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 R410A 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 40% and air velocity varying from 0.68 to 1.6 m/s. Experiments show that air velocity decreased by 16% is needed for R410A than that of R22 for subcooling temperature of 5$^{\circ}C$, which resulted in air-side pressure drop decrease of 15% for R410A as compared to R22. As a consequence, in order to provide the same design condition of a condenser, the fan requires lower electric-power consumption with R410A than that with R22.

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.

Performance of the Cooling and Heating of Heat Pump Using Non-azeotropic Refrigerant Mixtures (비공비혼합냉매를 이용한 열펌프의 냉난방성능에 관한 연구)

  • 박기원;오후규
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.4
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    • pp.53-61
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    • 1994
  • An experimental study on heat pump cycle systematizing characteristics for non-azeotropic refrigerant mixtures of R-22+R-114 was reported. Data were obtained under steady state condition at the ranges of parameters, 550- 2, 170kcal/h, 670-2, 990kcal/h, 24-71kg/h, and 0-1, for as cooling capacity, heating capacity, mass 25, 50, 75, and 100 per cent of R-22 by weight fraction for R-22+R-114 mixtures. The results shown that the C.O.P of the 50wt% of R-22 mixture was considerably larger than for pure R-22 and other weight fraction of R-22 mixtures, but the compression power of the 25wt% of R-22 was lower than that of the pure R-22 and the other weight fraction of R-22 mixtures. The hightest value of cooling capacity was obtained at the conditions of evaporating temperature 5.deg.C and R-22 50wt% mixture. In general, with an increase in the R-22 weight fraction for fixed values of the other parameter, the cooling capacity increased at first, obtained a maximum, and then decreasd. This verified the importance of accurate weight fractions od refrigerant mixtures in the heat pump cycle.

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The Friction Characteristics of the Journal Bearing in the Refrigerant Compressor

  • Cho, Ihn Sung;Baek, Il Hyun;Oh, Seok Hyung;Jung, Jae Youn
    • KSTLE International Journal
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    • v.1 no.2
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    • pp.113-117
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    • 2000
  • The rotary-vane compressor has become one of the most successful types of compressors because of its mechanical reliability, compactness, and adaptability to moderately high-speed operation in virtually an unlimited range of sizes. However recently, the depletion of the ozone layer due to the current refrigerant(R22) has been getting worse, and it is one of the world's pressing issues. In this paper, we will discuss the use of R410a in the compressor of a room air-conditioner as an alternative refrigerant and air-conditioning system to R22, since R410a has greater refrigerant characteristics than R22. Miniaturization of the rotary compressor for the new refrigerant and air-conditioning system is also possible, which reduces the prime cost of production, hence R410a is naturally a better refrigerant. But to apply the new HFC refrigerant system in refrigeration and air-conditioning systems, a significant redesign of the current refrigerant system is also required, because as the refrigeration changes, lubrication characteristics vary. Close attention must be paid to friction force and energy loss due to friction and wear at many sliding areas.

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Study on the Performance of Heat Pump Using Non-azeotropic Refrigerant Mixtures R-22+R-114 (비공비혼합냉매 R-22+R-114를 이용한 열펌프의 성능에 관한 연구)

  • 박기원;구학근;오후규
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.9
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    • pp.2131-2137
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    • 1993
  • This study, examines the performance and the heat pump cycle systematizing characteristics for non-azeotropic refrigerant systems. In order to conduct such an examination, the cycle characteristics of heat pumps for pure R-22, R-114, and their mixtures were experimentally investigated. The results show that cooling/heating capacities for the mixtures was more suited at the evaporating temperature of $5^{\circ}C$ than that of $0^{\circ}C$, $-5^{\circ}C$, and $-10^{\circ}C$. The C.O.P of the 50 wt% mixtures was considerably higher than for pure R-22, and the compression power of the 25 wt% was as much as 60% lower than that of pure R-22. Even small fractional mixture variations can lead to significant changes in the characteristics of the heat pump cycle. This experiment verified the importance of accurate weight fractions of refrigerant mixtures.

Forced Convective Evaporating Heat Transfer of Non-azeotropic Refrigerant Mixtures in a Horizontal Smoothed Tube (수평 평활관내에서 비공비혼합냉매의 강제대류 증발열전달)

  • Park, K.W.;Oh, H.K.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.2
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    • pp.225-233
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    • 1995
  • Experiments were performed to investigate the heat transfer characteristics of nonazeotropic mixture R-22+R-114 in a heat pump system. The ranges of parameter, such as heat flux, mass flow rate, and quality were $8,141{\sim}32,564W/m^2$, 24~58kg/h, and 0~1, respectively. The overall compositions of the mixtures were 50 and 100 per-cent of R-22 by weight for R-22+R-114 mixture. The results indicated that there were distinct different heat transfer phenomena between the pure substance and the mixture. In case of pure refrigerant the heat transfer rates for cooling were strongly dependent upon quality of the refrigerant. Overall evaporating heat transfer coefficients for the mixture were somewhat lower than pure R-22 values in the forced convective boiling region. For a given flow rate, the heat transfer coefficient at the circumferential tube wall(top, side, and bottom of the test tube) for R-22/R-114(50/50wt%)mixture, however, was higher than for pure R-22 at side and bottom of the tube. Furthermore, a prediction for the evaporating heat transfer coefficient of the mixtures was developed based on the method of Yoshida et.al.'s. The resulting correlation yielded a good agreement with the data for the refrigerant mixtures.

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A Study for Evaporation Heat Transfer Characteristic of R22/Rl14 Refrigerant Mixtures in a Horizontal Tube (수평증발관내 R22/R114 혼합냉매의 열전달 특성에 관한 연구)

  • 윤치한;이종인;하옥남
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.5
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    • pp.502-510
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    • 2000
  • Evaporation heat transfer characteristics were studied in a horizontal tube using R22/R114 non-azotropic refrigerant mixture. the heat transfer coefficient was high in the upper part for pure refrigerants, and heat transfer coefficient was low in the lower part for refrigerant mixtures. In the low quality region where nucleate boiling was dominant, the average heat transfer coefficient was low. In the region where forced convection was dominant, heat transfer coefficient was high. Results show that the heat transfer coefficient for pure refrigerants obtained by experiments were lower than those of Yoshida et al. but agreed well with Jung et al., and Chen et al. data. But the heat transfer coefficients for refrigerant mixtures were lower about 20% than those predicted by the equation for pure refrigerant.

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