• Title/Summary/Keyword: Cooling capability

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Performance Characteristics of Sub-Cooled Hybrid Condenser in Automotive Air-Conditioning System (자동차 공조시스템에서 건조기 일체형 응축기의 성능특성)

  • 김경훈;김석우
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.205-210
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    • 2004
  • Sub-cooled hybrid condenser(SCHC) which have been developed through this study is an appliance of integrating a condenser with a receiver dryer, which were previously separated. It is supposed that the development of sub-cooled hybrid condenser will be able to reduce not only weight, size, production process and cost, but also quite improve in capability, which will be of great use for the technological development and research of an air conditioning system whose importance is higher in a car. Through the present study it was found that the developed SCHC increases in the degree of sub-cooling by 10∼100% compared to conventional condenser. The excessive sub-cool has improved the cooling performance by 10%, and that leads to the reduction in evaporator outlet air temperature $1.5^{\circ}C$. Additionally, it is expected that sub-cooled hybrid condenser weights less by 100g than the previous condensers which has equal super heat.

Numerical analysis study of an optimal cooling system for desktop PC CPUs (데스크탑 PC용 CPU 냉각 시스템 최적화를 위한 수치해석 연구)

  • Choi, Jee-Hoon;Yoo, Jung-Hyun;Seo, Min-Whan;Kang, Shin-Jae;Kim, Chul-Ju
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2298-2303
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    • 2008
  • The increasing demands for the recently released CPU which has had higher heat density, the confined space of desktop PCs, and so on are the main drive for continuously improving PC cooling systems. In order to meet number of demands, this paper describes the flow and thermal behavior of the heat sink combined with heat pipes, and a fan through the numerical analysis by using the computational fluid dynamics(CFD) code and discusses how to extend the cooling capability.

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Analysis of Cooling Characteristics of Broadcasting LED Light with Ion Wind Generator (이온풍 공랭 방식 적용을 위한 방송용 LED 조명장치의 냉각 특성 해석)

  • Park, Chul-Woo;Lee, Seung-Jun;Kim, Dae-Joong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.9
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    • pp.693-698
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    • 2012
  • In the present work, numerical analyses of broadcasting LED light with ion wind generator have been carried out for enhancement of cooling performance. Ion wind generator is produced and experimented before analysis. With the use of result of experiments, broadcasting LED light model is computed. Ion wind velocity into LED light is varied with 0~3 m/s. Based on the numerical results, the area of duct-type ion wind generator was designed to reduce the volume flow rate of ion wind. The modified inlet geometry shows sufficient cooling capability. And, through modified ion wind generator, the volume flow rate of ion wind has been largely reduced.

A Study on Heat and Mass Transfer in a Vertical Tube Absorber Using LiBr Family Solutions (LiBr계 용액을 사용한 수직관 흡수기의 열 및 물질 전달에 관한 연구)

  • Cho, H.C.;Kim, C.B.;Jeong, S.Y.;Kang, S.W.;Lee, C.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.2
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    • pp.196-206
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    • 1995
  • Experimental investigations on heat and mass transfer characteristics in a vertical tube absorber have been carried out. Three different copper tubes with a length of 1.5m have been tested using LiBr solution and LiBr-$CaCl_2$ solution. The effects of solution flow rate, cooling water temperature, solution inlet temperature and evaporation temperature have been investigated in detail. It is found that heat transfer coefficient increases gradually with the increase of solution flow rate, but decreases rapidly for the flow rates less than 0.02kg/ms. The grooved tube generally shows better heat transfer performances than the smooth tube. LiBr solution shows almost no absorption capability for the cooling water temperatures over $40^{\circ}C$. LiBr-$CaCl_2$ gives less decreasing rate in absorption capability at these temperatures and the heat transfer coefficient becomes less dependent on the types of tubes in use. Considering heat and mass transfer rates, LiBr-$CaCl_2$ solution is found to be more suitable than LiBr solution for air cooled absorber, which operates at higher temperature than water cooled absorber.

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Application of the Geothermal Hybrid System for Huge Size Common Structures with Heating & Cooling System (지열 Hybrid System 개발을 통한 대형 공동구조물 지열에너지 적용성 평가)

  • Park, Si-Sam;Na, Sang-Min;Park, Jong-Hun;Rhee, Keon-Joong;Kim, Tae-Won;Kim, Sung-Yub
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.588-591
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    • 2009
  • Ground source heat pump system; GSHPs is close to most practical use for early stage investment cost and energy efficiency in new renewable energies, and currently considered utilizing to the heat and cooling system of a building. Particularly, the case to utilize 'Standing Column well heat source gathering method' in the open standards process to have the excellent capability of gathering geothermal source is increased. But the research for the optimal design technology and the assessment of a pollution level of the ground to utilize a single well for gathering geothermal is insignificant and the design is insufficient. The heating and cooling system and the equipment to utilize a large size residential development to have over 1000 households have not developed yet. Therefore, our company developed 'geothermal hybrid system' which can construct the heat and cooling system using geothermal energy for a large size residential development of over 1000 households and conducted the evaluation of economic feasibility. Moreover we developed automatic equipment for gathering geothermal source and PLC (Programmable logic controller) to have optimal efficiency and FCU (fan coil unit) considering the floors of large size apartments.

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A Study on Thermal Performance of Microchannel Waterblock for Cooling of CPU in Desktop (컴퓨터 CPU 냉각용 미세채널 워터블록의 열성능에 관한 연구)

  • Choi, Mi-Jin;Kwon, Oh-Kyung;Cha, Dong-An;Yun, Jae-Ho
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.264-269
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    • 2007
  • The microchannel waterblock has a good capability in the cooling of electronic devices. The object of this paper is to study on thermal performance of microchannel water block for cooling of CPU in desktop. The effects of header shape, liquid flow rate, and inlet temperature on the thermal performances of microchannel waterblock are investigated experimentally. Three types of waterblock with different header shape are manufactured from the micro milling and brazing processing. The experiments are conducted using water, over a liquid flow rate ranging from 0.7 to 2.0 LPM and inlet temperature ranging from 20 to $35^{\circ}C$. Waterblocks are attached both horizontally and vertically on the test section to anticipate a performance of waterblock under the actual state in computer. The base temperature and thermal resistance decrease with increasing of liquid flow rate. It was found that the sample #1 was appropriate for the prototype of liquid cooling system.

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Capability of Turbulence Modeling Schemes on Estimating the Film Cooling at Parallel Wall Jet-Nozzle Configuration (평행 벽 제트-노즐 형상에서 난류모델별 막냉각 예측 능력)

  • Lee, Jun;Kim, Yoo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.13 no.1
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    • pp.10-18
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    • 2009
  • Numerical simulation has been performed in this study to investigate the capabilities of turbulence modeling schemes on estimating the film cooling at a referenced parallel wall jet-nozzle configuration. Also a additional simulation has been performed for film cooling under 2-dimensional axis symmetry conditions at a parallel wall jet-nozzle configuration. It was concluded that the best turbulence model is the standard $k-{\epsilon}$ model with enhanced wall functions. Also a additional simulation showed the film cooling characteristics that are resonable physically.

Thermal Analysis of the Natural Convection Cooling Type Transformer

  • Oh Yeon-Ho;Song Ki-Dong;Sun Jong-Ho
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.5B no.2
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    • pp.142-145
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    • 2005
  • The life expectancy of a transformer largely depends on the temperature-rise it experiences. If the temperature-rise exceeds limits specified in the design standards, the aging of insulating materials is accelerated and the capability of the cooling medium is deteriorated. Consequently, applicable limits for the temperature-rise are essential in designing the transformer and the coolers, demanding the estimation of the transformer's thermal behavior. In order to analyze the temperature characteristics of the transformer, numerical analysis by way of the commercial CFD code has been carried out, and temperature-rise testing to verify computed results was performed. The results obtained in this study show that there is a good agreement between computed outcomes and experimental outcomes.