• 설비공학논문집
• /
• 제14권6호
• /
• pp.468-476
• /
• 2002

This paper deals with heat and mass transfer characteristics and performance evaluation of a counter flow double-tube condenser for a multi-component refrigerant mixture. The local heat and mass transfer characteristics of ternary zeotropic refrigerant mixtures composed of HFC32/HFC125/HFC134a are evaluated for a counter flow double-tube condenser cooled by water. Then, the local values of vapor quality, thermodynamic states at bulk vapor, vapor-liquid interface and bulk liquid, heat flux and condensation mass flux are obtained. The heat exchange performance for ternary zeotropic refrigerant mixtures composed of HFC32/HFC125/HFC134a on the total pressure drop and the heat transfer characteristics are also compared with those for R404A, R410A, R502, R22, R32, Rl23 and R134a.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
• /
• pp.250-257
• /
• 2002

A centrifugal compressor for HFC-l34a has been newly designed and developed. Flow analysis using commertial programs was used to evaluate performance and internal flow of the impeller, inlet guide vane and diffuser etc. and design software was developed. The compressor for HFC-l34a was also investigated experimentally to check compression performance. The calculated data coincide the test results of compressor. The data obtained in the present study are useful for design of HFC-l34a centrifugal compressors.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.1945-1950
• /
• 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
• /
• 제8권1호
• /
• pp.45-54
• /
• 1996

An experimental investigation on the two-phase flow through tube orifices was performed with the refrigerant mixture of R32/125/134a(30/10/60). A series of tests were conducted to generate wide range of data at varying operation conditions with four short tubes. The tests include both single and two-phase flow conditions at the inlet of the short tube with different oil concentrations. Experimental data were presented as a function of major operating parameters and short tube diameter. Based on test results and data analysis, a semi-empirical flow model was developed to predict the mass flow rate through short tube orifices with a given set of conditions. The flow model was formed to cover both single and two-phase flow at the inlet of short tube with considering the effects of oil concentration.

• Journal of Advanced Marine Engineering and Technology
• /
• 제35권1호
• /
• pp.40-45
• /
• 2011

본 연구의 목적은 팽창장치 후에 설치된 액기분리기와 예냉 열교환기를 갖는 냉동시스템의 특성을 파악하고자 하는 것이다. 냉장고의 전형적 냉매인 냉매 R134a의 팽창공정 후 액기분리기에서 분리된 찬 증기를 이용하여 예냉 열교환기에서 팽창장치에 주입되는 냉매를 과냉시킨다. 분석결과 냉동능력은 8.9% 상승하였으며, COP는 1.4% 증가하였다. 이러한 성능 향상의 이유는 냉매 모리엘선도의 포화액선과 포화기체선의 기울기가 다르기 때문이다.

• 한국자동차공학회논문집
• /
• 제11권4호
• /
• pp.196-203
• /
• 2003

This study was performed to design the optimal block type expansion valve through analyzing the characteristics of the block type expansion valve in automotive air conditioning system using HFC-134a. Because an alternative refrigerant (HFC-l34a) is being used instead of CFC-12 for automotive air conditioning system, newly designed air conditioning components are necessary due to changes in characteristics. The performance tests were accomplished through the test bench, that is manufactured based on the study. And then it was carried out to measure the variation of temperature and pressure at each part of the air conditioning system according to the compressor speed.

• 설비공학논문집
• /
• 제17권8호
• /
• pp.729-735
• /
• 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.

• 대한설비공학회지:설비저널
• /
• 제39권2호
• /
• pp.10-16
• /
• 2010

현재의 자동차용 HFC-134a 에어컨시스템을 대체하기 위하여 세계적으로 소개되고 있는 지구온난화 규제 대응 대체냉매와 이를 적용한 에어컨 시스템 개발 동향을 소개하고자 한다.

• 설비공학논문집
• /
• 제24권12호
• /
• pp.823-829
• /
• 2012

In this study, the performance of mobile air conditioner(MAC) systems to which the refrigerants R134a and R1234yf were used was evaluated to compare the characteristic of automotive refrigeration cycles with refrigerant. The experimental setup of a MAC consists of an belt driven compressor, a condenser, an evaporator and a block type thermal expansion valve. The drop-in test on MAC were carried out under variable compressor speed from 800 to 2500 rpm. Performance test by using R1234yf and R134a in the same system revealed low the charge amount and mass flow rates for using R1234yf, that is, up to 10% and 17%, respectively. The compressor discharge temperature of R1234yf is $8^{\circ}C$ lower than that of R134a. The cooling capacity with R1234yf system decreased by 4~7% compared with R134a system. In addition, The COP of R1234yf system is lower 3~4% than that of R134a system.

• 한국자동차공학회논문집
• /
• 제15권6호
• /
• pp.170-176
• /
• 2007

It is time to prepare the phaseout of R134a, the current refrigerant, in automotive air conditioning system because the EC deadline has been coming with new platform vehicles in 2011 and all vehicles by 2017. Until now a high-pressure carbon dioxide($CO_2$) system is the leading replacement of R134a in European auto-makers but there is no firm agreement in the world automotive market. Recently three new fluids have been announced as the possibilities from Honeywell, DuPont and INEOS Fluor. The new alternative refrigerant should meet the requirements like non flammable, non toxic, no ozone depletion effect and low GWP(under 150 to meet EC regulation). The objectives of this paper are to review the fluid H from Honeywell, the more possible alternative refrigerant in 3 new fluids, compare the properties of R134a & fluid H and see the possibility as a replacement of R134a. In this experimental paper we ran and reviewed the cooling performance data in the bench system, the vehicle and the field test. We found the possibility of fluid H system to meet the R134a system performance with some hardware modifications but agreed that it is still needed to study about the long term safety, environmental effects, material compatibilities and so on.