• 설비공학논문집
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• 제15권12호
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• pp.1007-1017
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• 2003

An experimental study on the air-side pressure drop and heat transfer coefficient of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side heat transfer coefficients in the literature is not based on a consistent approach. This paper focuses on new method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry and wet surface heat transfer estimation in fin-tube heat exchanger having refrigerant on the tube-side. Results are presented as plots of friction f-factor and Colburn j -factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of 150∼250 kg/$m^2$s with air flows at velocity ranges from 0.3 m/s to 0.8 m/s.

• 에너지공학
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• 제16권3호
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• pp.149-154
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• 2007

본 연구에서는 슬릿 휜-관 열교환기의 공기측 압력강하 특성을 실험적으로 고찰하였다. 물을 작동유체로 사용한 기존의 실험은 공기측 압력강하에 대해 일관된 방법을 제시하지 못하고 있다. 따라서 본 연구에서는 R22를 적용하여 휜-관 열교환기의 전표면과 습표면에 공기측의 압력강하 특성을 나타내는 표준 방법을 제시하고자 하였다. 기존의 실험 상관식과 본 연구에서 제시한 실험 데이터를 증발기와 응축기의 설계조건에서 레이놀즈수와 f-factor의 관계식으로 나타내었다. 본 실험은 공기의 속도가 $0.38{\sim}1.6\;m/s$ 일 때 냉매의 질량 유속 범위를 $150{\sim}250\;kg/m^2s$하여 수행하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.192-197
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• 2008

The objectives of this paper are to measure the heat transfer and pressure drop of the heat transfer tube for an evaporator of absorption system applications. Five types of heat transfer tubes with different shape and heat transfer area are tested in the present experiment. Heat transfer and pressure drop performance of heat transfer tubes are measured in various operating conditions, and compared each other. The results show that the heat transfer rate of thermoexcel notch tube and low fin tube increases about 27.6% and 11.6% at the refrigerant flow rate 250 kg/h compared with that of bare tube, respectively. The thermoexcel notch tube is shown the best performance considering pressure drop and heat transfer coefficient.

• 설비공학논문집
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• 제16권3호
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• pp.230-240
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• 2004

An experimental investigation was conducted to study two-phase flow distribution in a T-type distributor of slit fin-and-tube heat exchanger using R22. A comparison was made between the predictions by previously proposed tube-by-tube method and experimental data for the heat transfer rate of evaporator. Experiments were carried out under the conditions of saturation temperature of 5$^{\circ}C$ and mass flow rate varying from 0.6 to 1.2kg/min. The inlet air has dry bulb temperature of 27$^{\circ}C$, relative humidity of 50% and air velocity varying from 0.63 to 1.71㎧. Experiment show that air velocity increased by 85.2% is need for T-type distributor with four outlet branches than that of two outlet branches under the superheat of 5$^{\circ}C$, which resulted in air-side pressure drop increase of 130% for T-type distributor with four outlet branches as compared to two outlet branches.

• International Journal of Air-Conditioning and Refrigeration
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• 제13권4호
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• pp.184-195
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• 2005

This paper describes the recent work on advanced technology concepts applied to air cooled heat exchangers for residential air-conditioning. The concepts include vortex generators for the air-side, micro-fin or flat tubes for the refrigerant-side. Advances in understanding of heat transfer mechanisms, predictive models are discussed.

• 설비공학논문집
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• 제7권1호
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• pp.161-170
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• 1995

This study is concerned with the numerical analysis of performance on fin-tube heat exchanger under frosting condition. In this work, tube-by-tube method using LMED is employed. The present results are compared with O'Neal's experimental and numerical results. A standard evaporator model with 2rows-2columns is selected to investigate the effects of the various parameters such as fin pitch, air flow velocity, and humidity. The results show that frost thickness and the amount of frost per unit area decrease as fin-pitch becomes narrower. In the meantime, frost thickness and accumulation rate increase with higher inlet air humidity. It is shown that heat transfer rate increases during 30minutes and then it decreases. Heat transfer rate and the amount of frost increase with air velocity, however frost thickness does not increase over a certain velocity.

• 설비공학논문집
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• 제14권10호
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• pp.781-785
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• 2002

The effects of different surfaces on dry and wet frosting test were experimentally investigated. The results of experiment were compared by the performance evaluation coefficient (PEC). Results showed that the air-side pressure drop of lacquer coated evaporator increased by 5% as compared to the plasma treated one. It was also found that the Plasma coated evaporator is lower than lacquer coated one in the PEC ratio.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.483-488
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• 2006

In this study, newly-developed slim electronic panel cooler with aluminum PF condenser and evaporator was tested and the results are compared with imported panel cooler with fin-tube heat exchangers. The PF heat exchangers significantly (approximately 45%) reduced the refrigerant charge. The air-side pressure drop was also reduced, which resulted in the reduction of the sound level of the panel cooler. The effect of the condenser size was also investigated.

• 설비공학논문집
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• 제21권4호
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• pp.215-221
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• 2009

The objectives of this paper are to measure the heat transfer and pressure drop of the heat transfer tube for an evaporator of absorption system applications. Five types of heat transfer tubes with different shape and heat transfer area are tested in the present experiment. Heat transfer and pressure drop performance of heat transfer tubes are measured in various operating conditions, and compared each other. The results show that the heat transfer coefficient of thermoexcel notch tube increases about 79.6% and 45.3% at the film Reynolds number 69.7 compared with that of bare tube and low fin tube, respectively. The thermoexcel notch tube is show the best performance considering pressure drop and heat transfer coefficient.

• 설비공학논문집
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• 제10권1호
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• pp.44-55
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• 1998

The evaluation of aluminum flat tube and louver fin heat exchangers for a condenser in residential air-conditioning applications has been conducted. A series of tests for two-different brazed aluminum heat exchangers was performed and the results were compared with conventional fin and tube heat exchangers for residential air-conditioning system. Refrigerant charge amount for a window-system air-conditioner with the brazed aluminum condenser is decreased by 35% and the volume and material of heat exchanger can be reduced by 50% compared to the conventional fin and tube heat exchangers.