• Title/Summary/Keyword: Louver-fin

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The Experimental Study on Performance Improvement under frost conditions of the Heat Pump with Corrugate Shaped Fin and Two Compressors (저 착상 휜과 두 대 압축기 사이클을 이용한 히트펌프 난방성능 개선에 관한 연구)

  • Hwang Yoon-Jei;Cho Eun-Jun;Chung Baik-Young;Lee Gam-gue
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.3
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    • pp.201-208
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    • 2005
  • This study presents the experimental study on improvement of frost/defrost performance in an heat pump system with newly developed fin and multiple compressors. As multiple compressors system, the variable and single speed compressor combinations has been introduced and compared with single speed 1-compressor system in a view point of improvement of frost/defrost performance. Also, newly developed corrugate shaped fin has been compared with conventional louver shaped fin. The frost/defrost performance is defined and some parameters are compared to discuss the effect of each combination. From this experimental study, it is known that if the variable and single speed compressor combination system equipped with corrugate shaped fin, the system performance has greatly improved not only for heating capacity, but also for frost performance.

Heat Transfer and Fluid Flow Evaluation of Radiator for Computer Cooling (컴퓨터용 라디에이터의 열전달 및 유동특성 평가)

  • Cha, Dong-An;Kwon, Oh-Kyung;Yun, Jae-Ho;Oh, Myung-Do
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.1153-1158
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    • 2009
  • The performance of louver-finned flat-tube and fin & tube radiators for computer CPU liquid cooling were experimentally investigated. In this study, 7 samples of radiators with different shape and pass number (1, 2, 10) were tested in a wind tunnel. The experiments were conducted under the different air velocity range from 1 to 4 m/s. The water flow rate through a pass was 1.2 LPM. Inlet temperatures of air and water were $20^{\circ}C$ and $30^{\circ}C$ respectively. It was found that the best performance was observed in the louver-finned flat-tube sample considering pressure drop and heat transfer coefficient.

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Experimental Study on the Performance Change of the Fin and Tube Type Heat Exchanger by the Frosting (착상에 의한 휜관형 열교환기의 성능변화에 관한 실험적 연구)

  • Kim, Jung-Kuk;Koyama, Shigeru;Kuwahara, Ken;Park, Byung-Duck;Kim, Dong-Hwi;Sa, Yong-Cheol
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.2
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    • pp.79-86
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    • 2009
  • The present study was investigates the effect of the parameters on the frost formation and heat transfer performance such as fin shape, air temperature and air velocity. Heat transfer rate and pressure drop by frost were experimentally investigated. Effect of the wet blub temperature and air velocity on the heat transfer performance has been also investigated. The heat transfer performance of the louver fin and tube type heat exchanger was higher by maximum of 0.85% than the corrugate fin type at the air temperature of $2.0/1.5^{\circ}C$. As the wet blub temperature of air were increased, the heat transfer rate, pressure drop and mass of frost of three test models were increased. Especially, the maximum heat transfer rate and maximum pressure drop were shown for the Type B louver fin heat exchanger. As an experimental result, the enhancement factor(EF) of louver fin and tube type heat exchanger was only $0.2{\sim}0.4$ due to the high pressure drop.

Heat Transfer and Friction Characteristics of Louver Fin and Tube Heat Exchangers under Wet Conditions (루버핀-관 열교환기의 습조건에서의 열전달 및 마찰특성에 대한 실험 연구)

  • Kwon, Young Chul;Chang, Keun Sun
    • Applied Chemistry for Engineering
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    • v.19 no.1
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    • pp.73-79
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    • 2008
  • An experimental study was conducted to investigate the effect of a tube row, a fin pitch and an inlet humidity on air-side heat and mass transfer performance of louvered fin-tube heat exchangers under wet conditions. Experimental conditions were varied by three fin pitches, two rows, two inlet relative humidities. Experimental results showed that the heat transfer performance decreased and the friction increased with the decrease of fin pitch, for 2 row heat exchanger. The effect of fin pitch on heat transfer performance was negligible with 3 row heat exchanger. The changes in relative humidity was not affected heat transfer and friction. However, the mass transfer performance was slightly decreased with the increase of relative humidity and with the decrease of fin pitch. The mass transfer performance of the louvered fin-tube heat exchanger decreased with the decrease of the fin pitch and was different according to the number of tube row.

Experimental Study on the Airside Performance of Aluminum Heat Exchangers Having Slim Louver Fins (슬림형 루버 핀이 장착된 알루미늄 열교환기의 공기측 전열 성능에 대한 실험적 연구)

  • Kim, Nae-Hyun;Cho, Honggi
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.9
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    • pp.587-595
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    • 2017
  • Recent trends in slim air conditioners require heat exchangers of reduced flow depth. In this study, slim louver fin geometry was obtained using predictive correlations. The deduced geometry yielded 10 mm flow depth, 0.9 mm louver pitch, and $35^{\circ}$ louver angle. Samples were made and tests were conducted. The new slim sample yielded 36% higher j factor and 2.3% higher f factor compared with those of the standard sample. This implies that 26% reduction of heat exchanger volume was possible by reducing the flow depth. In addition, the $j/f^{1/3}$ of the slim sample was 55% larger than that of the standard sample. Furthermore, the results are compared with predictions made using existing correlations.

Heat Transfer Enhancement by the Combined Effect of Louver Angle and Angle of Attack of Vertex Generator (와류발생기의 충돌각과 루버각의 상호작용에 의한 열전달촉진)

  • 박병규;정재동;이준식
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.6
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    • pp.477-484
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    • 2002
  • A numerical investigation of the performance of the plate heat exchanger with rectangular winglet is conducted to examine the combined effect of vortex generator and louver fins. Velocity and temperature fields and spanwise averaged Nu and friction factor are presented. Enhancement of heat transfer and flow loss penalty is evident. A Parametric study of three factors (Re, angle of attack and louver angle) with levels of 5 (Re= 300, 500, 700, 900, 1100), 4($\alpha=15^{\circ}, 30^{\circ}, 45^{\circ}, 90^{\circ},$), and 4($\beta=0^{\circ}, 15^{\circ}, 30^{\circ}, 45^{\circ}$), respectively, indicates the performance defined by the ratio of heat transfer enhancement to flow loss penalty shows monotonic behavior for each parameter alone but the interactions between parameters is found to be considerable effect on the performance of heat exchanger and should be considered in design. The effect of stamping is also examined.

A Study on Heat Transfer and Fluid Flow Characteristics of Radiator for Computer CPU Cooling (컴퓨터 CPU 냉각용 방열기의 열유동특성에 관한 연구)

  • Cha, Dong-An;Kwon, Oh-Kyung;Yun, Jae-Ho
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.23 no.1
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    • pp.1-7
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    • 2011
  • The performance of louver-finned flat-tube and fin and tube radiators for computer CPU liquid cooling was experimentally investigated. In this study, 7 samples of radiators with different shape and pass number (1, 2, 10) were tested in a wind tunnel. The experiments were conducted under the different air velocity ranged from 1 to 4 m/s. The water flow rate through a pass was 1.2 LPM. Inlet temperatures of air and water were $20^{\circ}C$ and $30^{\circ}C$ respectively. It was found that the best performance was observed in the louver-finned flat-tube sample considering pressure drop and heat transfer coefficient.

Analysis Study of Performance of CO2 Microchannel Evaporator According to Frost Growth (서리성장에 따른 이산화탄소용 마이크로채널 증발기의 성능에 관한 해석적 연구)

  • Shin, Eun-Sung;Cho, Hong-Hyun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.10
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    • pp.724-732
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    • 2012
  • The microchannel evaporator with louver fin using carbon dioxide are analyzed according to the frost growth. To predict the performance of microchannel evaporator with the frost growth under low temperature, the simulation condition of previous studies was applied. As a result, the frost thickness increases and its increasing rate is reduced when the operating time increases. Frost thickness increases gradually below the quality of 0.74, and then it decreases rapidly. In addition, the frost growth of present model under same surface temperature is very similar trends with Moallem's test results. In case of low temperature application, the dimensionless frost thickness increases dramatically and it is about 0.86 after 10 minutes.

An Experimental Study on the Supplemental Cooling and Heating Performance Using 1 kW Thermoelectric Module for Vehicle (열전모듈을 이용한 자동차용 1 kW급 보조 냉난방 시스템의 성능에 관한 실험적 연구)

  • Lee, Dae-Woong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.5
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    • pp.224-230
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    • 2014
  • The purpose of this paper is to investigate the performance of supplemental cooling and heating system equipped with the 1 kW thermoelectric module. The system consist of 96 thermoelectric modules, heat sink with louver fin and water cooling jacket which is attached on the hot side of the thermoelectric module. The cooling and heating performance test of the thermoelectric system is conducted with various conditions, such as intake voltage, air inlet temperature, air flow volume, water inlet temperature and water flow rate at calorimeter chamber in consideration of environmental conditions in realistic vehicle drive. The experimental results of a thermoelectric system shows that the cooling capacity and COP is 1.03 kW, and 1.0, and heating capacity and COP is 1.53 kW, and 1.5 respectively.

Performance Comparison of 7mm Fin-Tube Heat Exchangers for Various Design Conditions (설계 조건에 따른 7mm 직경 핀-관 열교환기의 성능비교)

  • Chang, Keun-Sun;Kim, Hyuk;Hong, Seok-Ryul;Kim, Young-Jae
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.633-638
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    • 2006
  • This study presents the air side heat transfer and friction characteristics of fin-tube heat exchangers with various fin types. A total of 8 samples of heat exchangers are tested. Fin patterns tested are slit, louver and plate fins. Each fin type has three cases of number of tube rows(N=1, 2, 3) and two different fin pitches. The results are plotted in terms of Colburn j-factor and friction factor f with respect to Reynolds number in the range of 200 to 510.

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