• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.4
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• pp.285-292
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• 2002

The vapor pressure and miscibility measurement apparatus was developed and used to obtain data for refrigerant/oil mixture. The vapor pressure and miscibility data for R-404A/32 ISO VG polyol ester (POE) oil mixture and R-404A/46 ISO VG polyol ester oil mixture are obtained over the temperature range from -20 to $60^{\circ}$ with at $10^{\circ}$ intervals and the oil concentration range from 0 to 70 wt%. Using the experimental data, an empirical model was developed to predict the temperature vapor pressure-concentration relations for R-404A/46 ISO VG polyol ester oil mixtures at equilibrium. In the R-404A/32 ISO VG polyol ester oil mixture, the average root-mean-square deviation between measured data and calculated results from the empirical model is 1.24% and in the R-404A/46 ISO VG polyol ester oil mixture, that is 1.37%. Miscibility for R-404A/32 ISO VG polyol ester oil mixture was observed all over the experimental conditions. Immiscibility for R-404A/So1est 46 oil mixture was observed at the low oil concentrations (20~30 wt%) over the high experimental temperature range (50~$60^{\circ}$).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.10
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• pp.718-725
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• 2007

In the general vapor-compression refrigeration system, refrigeration lubricant circulates in refrigeration system with refrigerant. Knowledge of the amount of circulating lubricant is very important to exactly calculate capacity of the refrigeration system. An experimental study was conducted to estimate the oil concentration of a flowing $CO_2/Oil$ mixtures. POE and PAG oil are considered as test lubricants in this study. Performance tests were conducted under simulated liquid conditions for $CO_2/POE$ oil mixture in oil concentration of 0 to 10 weight-percent and $CO_2/PAG$ oil mixture in oil concentration of 0 to 6 weight-percent in the temperature ranges of $-5^{\circ}C\;to\;15^{\circ}C$. The results obtained indicate specific gravity of $CO_2/Oil$ mixture is increased as oil concentration is increased and as temperature of mixture is decreased. Oil concentration correlation of $CO_2/POE$ oil mixture and $CO_2/PAG$ oil mixture is suggested, based on the measurement of specific gravity and temperature. This correlation enable to predict the oil concentration without extraction of the mixture and can be applied for $CO_2/POE$ mixtures and $CO_2/PAG$ mixtures.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.3
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• pp.255-262
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• 2014

To investigate the effect of oil on evaporation heat transfer of plate heat exchanger, evaporation heat transfer experiment was carried out using experimental apparatus for micro gear pumped R134a-oil circulation. By varying oil circulation rate of POE oil from 0 to 5%, evaporation heat transfer performance of plate heat exchanger was investigated. As OCR(Oil Circulation Ratio) increases, the evaporation heat transfer coefficient of R134a decreases and pressure drop increases. When the evaporating temperature is $30^{\circ}C$ and the refrigerant mass flow rate is 80 g/s, evaporation heat transfer rate decreases by 10 % and pressure drop increases by 10% at 2% of OCR condition.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.4
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• pp.473-483
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• 1996

To protect the ozone layer, R22 will be replaced with HFCs. R407C is a leading candidate as alternative refrigerant for air conditioner due to its similar thermodynamic characteristics with R22. In replacing R22 with R407C, the compatibility with lubricating oil is of major concern. Polyol ester (POE) oil among the synthetic oils is considered to be the best lubricant for use with R407C because of good electrical properties and miscibility. However, lubricating ability of mixture of R407C/POE oil is lower than that of R22/mineral oil due to the production of acid by hydrolysis which causes corrosive wear. Therefore, to minimize water content, it is needed to develop a molecular sieve desiccant which is compatible with R407C and ester oil. This paper discusses (1) the change of properties of POE oil when current molecular seive is used, (2) the effects of POE oils and additives on durability of compressor. Through compressor life test and bench wear test, it was found that inadequate use of POE oils and additives may promote the deteriation of molecular sieve, resulting in decrease of durability of compressor.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.20-40
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• 1996

The oil in water type ME of 4 component system was composed with POE monoalkyl ether and POE sorbitan monoalkyl ester as surfactant, saturated hydrocarbon, side chain structure and aromatic structure as oil, and glycerine as cosurfactant using high pressure homogenizer. The objective of this study was to examine the role of surfactant and oil structure on droplet size and stability. The experimental results showed that the droplet size was smaller with bigger polarity of oil, less hydrocarbon, longer hydrophilic chain of surfactant and higher concentration of glycerine. SQ and LP systems showed very stable but AB and ISB system unstable microemulsion.

• Journal of the Korean Applied Science and Technology
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• v.12 no.2
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• pp.13-19
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• 1995

Spin finish(SF) for nylon filament was prepared. The influence on the properties of filament obtained by treating the prepared spin finish in this study(SF-2) and foreign-made spin finish(Spinnar N-100) was compared. SF-2 prepared by blending of spindle oil 70g, paraffin wax 10g, glyceryl mono-oleate 5g, POE(6) nonylphenyl ether 4g, POE(10) nonylphenyl ether 4g, POE(10) octylphenyl ether 2g, POE(14) mono-oleate 4g and water 1g was excellent in its characteristics. Some of the properties of Nylon filament treated with SF-2 were better than those treated with Spinnar N-100. Also, optimal physical conditions of nylon filament according to the number of revolution of oil roller were obtained at conditions of 5rpm of number of revolution oil roller, 1.25% of SF-2 oil pick up, and denier 69D.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.145-152
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• 1996

A fine oil-in-water (O/W) emulsion using nonaqueous emulsification technique was developed and the behaviors of POE(25)octyldodecyl ether in nonaqueous solvent/oil systems were studied by observing the surface tension, interfacial tension, turbidity and transition temperature. It was found that POE(25)octyldodecyl ether existed soluble in nonaqueous solvent while, in aqueous system, it formed micelles. So, when a solvent, like glycerine in which POE(25)octyldodecyl ether has poor solubility, was added, POE(25)octyldodecyl ether moved to the surface. After saturated at surface, POE(25) octyldodecyl ether began to precitate. The mean particle size of the final emulsion was 230nm. Also, the emulsion system was stable at 0, 25, 40, $50^{\circ}C$ and cycling test for a month, while the conventional emulsion system showed unstability. It is concluded that, by pertinent combination of solvents, the adsorption efficiency of surfactant could be improved.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1672-1677
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• 2003

Carbon dioxide($CO_2$, R-744) has become a very popular issue in application to refrigeration and air conditioning systems as a natural refrigerant. An experimental study has been carried out to investigate the vapor pressure and miscibility of refrigerant R-744 in the presence of lubricant oil. This is of particular interest in the selection of the lubricant oil for the compressor of a refrigeration system or an air conditioning system using the refrigerant R-744. This apparatus consists of the test section, measuring devices, the vacuum pump, the constant temperature bath and relevant connecting pipes made of stainless steel. Two lubricant oils, such as mineral oil(Naphthenic) and polyol ester(POE) oil, are considered in the present study. For this purpose, test runs were conducted with the oil concentration range from 5 to 50 wt%, and the temperature range from -10 to $10^{\circ}C$ with $2^{\circ}C$ intervals. The results are correlated with the vapor pressure. and showed with the miscibility as visualization for the individual text components.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.1
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• pp.1-8
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• 2001

This paper deals with refrigerant-oil mixtures in a dehumidifying cycle. Two different oils such as Alkylbenzene(AB) and Polyol-esters(POE) lubricants are used for R134a to investigate the effect of miscibility on oil returnability. It was found that R134a/AB mixture had more unstable interface between oil and refrigerant than R134a/POE mixture. However, overall flow patterns of both refrigerant-oil mixtures were almost same. The minimum height of oil measured in the compressor was as high as twice of the least permissible height of oil in the compressor required to insure its reliability. Thus, it is considered that immiscible oil, i. e., AB for R134a can be used without causing oil returnability problem.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.3
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• pp.213-219
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• 2007

An experimental apparatus was constructed to obtain vapor-liquid equilibrium data for $CO_2/oil$ mixtures using mass analysis method with sample cylinder. Lubricants employed were POE (poly-ol ester) and PAG (poly alkylene glycol). The phase equilibria of $CO_2/oil$ mixtures prevailed in an equilibrium cell were observed through a couple of sight glasses at the opposite ends. Data were obtained over the temperatures $-10^{\circ}C,\;-5^{\circ}C,\;0^{\circ}C,\;5^{\circ}C,\;10^{\circ}C,\;25^{\circ}C,\;40^{\circ}C,\;60^{\circ}C,\;and\;80^{\circ}C$ under pressures up to 14 MPa and then mole fractions were calculated, respectively In general, more solubility of $CO_2$ is observed in POE than in PAG. Miscibility gap is closed for $CO_2/POE$ mixture but not for $CO_2/PAG$.