• Title/Summary/Keyword: Thermal management

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Thermal Management Study of PEMFC for Residential Power Generation (가정용 연료전지 시스템의 열관리 해석)

  • Yu, Sang-Seok;Lee, Young-Duk;Ahn, Kook-Young
    • Proceedings of the KSME Conference
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    • pp.2839-2844
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    • 2008
  • A PEMFC(proton exchange membrane fuel cell) is a good candidate for residential power generation to be cope with the shortage of fossil fuel and green house gas emission. The attractive benefit of the PEMFC is to produce electric power as well as hot water for home usage. Typically, thermal management of vehicular PEMFC is to reject the heat from the PEMFC to the ambient air. Different from that, the thermal management of PEMFC for RPG is to utilize the heat of PEMFC so that the PEMFC can be operated at its optimal efficiency. In this study, dynamic thermal management system is modeled to understand the response of the thermal management system during dynamic operation. The thermal management system of PEMFC for RPGFC is composed of two cooling circuits, one for controling the fuel cell temperature and the other for heating up the water for home usage. Dynamic responses and operating strategies of the PEMFC system are investigated during load changes.

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The Trend of System Level Thermal Management Technology Development for Aero-Vehicles (항공기 시스템 레벨 열관리 기술개발 동향)

  • Kim, Youngjin;Son, Changmin
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.1
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    • pp.35-42
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    • 2016
  • Modern aircraft is facing the increase of power demands and thermal challenges. In accordance with the application of more electric technology and advanced mission requirement, aircraft system requires increase of power generation and it cause increase of internal heat generation. Simultaneously, restrictions have significantly been imposed to the thermal management system. Modern aircraft must maintain low radar observability and infra-red signature. In addition, new composite aircraft skins have reduced the amount of heat that can be rejected to the environment. The combination of these characteristics has increased the challenges faced by thermal management. In order to mitigate the thermal challenges, the concept of system level thermal management should be applied and new modeling and simulation tools need to be developed. To develop and utilize system level thermal management technology, three key points are considered. Firstly, the performance changes of subsystems and components must be assessed at an integrated thermal system. It is because that each subsystem and component interacts with other subsystems or components and it can directly effects on overall system performance. Secondly, system level thermal management requirements and solutions must be evaluated early in conceptual design process as vehicle and propulsion system configuration decisions are being made. Finally, new component level thermal management technologies must focus on reducing heat generation and increasing the availability of heat sinks.

Using Natural Graphite Heat Spreaders to Increase CCFL LCD Operating Temperatures

  • Norley, Julian;Shives, Gary D.;Reis, Brad;Schober, John
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.273-276
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    • 2007
  • A natural graphite heat spreader increased the upper operating temperature limit of a CCFL backlit LCD television. A 0-80W heat source was used to simulate additional electronics. Without the heat spreader, internal circuitry shut-down at ${\sim}30;$ no shut-down occurred above 80W with a heat spreader. Additionally, brightness, temperature uniformity, and operating ranges were improved, verified by environmental chamber performance testing at various ambient conditions.

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Performance Characteristics of the Thermal Management System for Passenger Hydrogen Fuel Cell Vehicle (수소연료전지 자동차의 열관리시스템 성능특성에 관한 연구)

  • Lee, Ho-Seong;Won, Jong-Phil;Cho, Chung-Won;Lee, Moo-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.3
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    • pp.986-993
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    • 2012
  • The objective of this study is to investigate performance characteristics of the thermal management system for passenger hydrogen fuel cell vehicle under various operating conditions. The thermal management systems comprised of a stack cooling system, an electric device cooling system and an air conditioning system for a passenger room were tested with driving conditions. As a result, in highway driving mode, the cooling performance of the stack cooling system with air conditioning on condition was 28.8 % lower than that of the air conditioning off condition. And cooling load of the electric cooling system in the city driving mode was 65.6% higher than that of the highway driving mode.

Experimental Study on the Mutual Influence of Thermal Management System for Hydrogen Fuel Cell Vehicle (수소연료전지 자동차 열관리 시스템의 상호 영향도 분석을 위한 실험적 연구)

  • Lee, Moo-Yeon;Won, Jong-Phil;Cho, Choong-Won;Lee, Ho-Seong
    • Transactions of the Korean hydrogen and new energy society
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    • v.22 no.6
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    • pp.852-858
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    • 2011
  • This paper is aiming to estimate the mutual influence of the stack cooling performances with the operation modes of the thermal management system for the hydrogen fuel cell vehicles. The heat capacity of the thermal management system was measured by varying the operating modes such as stack cooling heat exchanger only (Mode 1), stack cooling and electric devices cooling heat exchangers (Mode 2), and stack cooling and electric devices cooling heat exchangers with an operation of the condenser (Mode 3).As the results, Performance of the thermal management system (TMS) at Mode 3 decreased up to 34.0%, compared with the result of the Mode 1. In addition, in order to optimize the performance of TMS, the entropy change of stack cooling heat exchanger using irreversibility analysis technique was analyzed with the relationship between entropy generation and entering air velocity of the thermal management system.

Model Based Hardware In the Loop Simulation of Thermal Management System for Performance Analysis of Proton Exchange Membrane Fuel Cell (고분자전해질 연료전지 특성 해석을 위한 열관리 계통 모델 기반 HILS 기초 연구)

  • Yun, Jin-Won;Han, Jae-Young;Kim, Kyung-Taek;Yu, Sang-Seok
    • Transactions of the Korean hydrogen and new energy society
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    • v.23 no.4
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    • pp.323-329
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    • 2012
  • A thermal management system of a proton exchange membrane fuel cell is taken charge of controlling the temperature of fuel cell stack by rejection of electrochemically reacted heat. Two major components of thermal management system are heat exchanger and pump which determines required amount of heat. Since the performance and durability of PEMFC system is sensitive to the operating temperature and temperature distribution inside the stack, it is necessary to control the thermal management system properly under guidance of operating strategy. The control study of the thermal management system is able to be boosted up with hardware in the loop simulation which directly connects the plant simulation with real hardware components. In this study, the plant simulation of fuel cell stack has been developed and the simulation model is connected with virtual data acquisition system. And HIL simulator has been developed to control the coolant supply system for the study of PEMFC thermal management system. The virtual data acquisition system and the HIL simulator are developed under LabVIEWTM Platform and the Simulation interface toolkit integrates the fuel cell plant simulator with the virtual DAQ display and HIL simulator.

Study on the Performance Characteristics of the Thermosyphon Used for the Vehicle Operated at Low Temperature Conditions (저온작동 조건에서 자동차용 써모사이폰의 성능특성에 관한 연구)

  • Lim, Taek-Kyu;Lee, Ho-Seong;Won, Jong-Phil;Cho, Chung-Won;Lee, Moo-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.2
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    • pp.510-515
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    • 2012
  • The objective of this study is to investigate low temperature performance characteristics of the thermosyphon with/without wick. Thermosyphons using water as the working fluid are tested with variations of wick, charge amount of the working fluid, outdoor temperature, and heat load for the evaporator section at a low temperature. As a result, the heat transfer of thermosyphon was optimized at the charge amount of 40% and increased with the rise of the outdoor temperatures.

Modeling Strategies and Thermal Management Performance of a Data Center with Cold-aisle Containment using CFD (컨테인먼트가 적용된 데이터센터의 CFD 모델링 기법 및 열 관리 성능 평가)

  • Ham, Sang-Woo;Jeong, Jae-Weon
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.31 no.1
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    • pp.159-166
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    • 2015
  • The main purpose of this study is to evaluate thermal management performance of data center with cold-aisle containment by using computational fluid dynamics (CFD) analysis. The main challenge of containment modeling in CFD is to consider the air leakage across the containment, which was neglected or considered based on the researchers' subjective assumption or complex measurement process. To properly evaluate the thermal management performance of containment, this study utilizes the building airtightness measurement data from building airflow simulation program (CONTAM) to model air leakage across containment. Based on the modeling strategy, the CFD simulation is conducted on modular data center test bed, and an experiment is also implemented in identical condition of CFD simulation. As a result, pressure distribution in the data center is properly modeled with the air leakage model, and the temperature measurement data are in good agreement with CFD results. Unlike intuition, the thermal management performance of containment is not excellent since there is some hot air recirculation through gaps between racks and the floor. This study also suggests that this recirculation can be alleviated by sealing the gaps between racks and the floor through CFD simulation.

Thermal Management of Proton Exchange Membrane Fuel Cell (고분자막전해질 연료전지의 열관리)

  • Yu, Sang-Seok;Kim, Han-Seok;Lee, Sang-Min;Lee, Young-Duk;Ahn, Kook-Young
    • Transactions of the Korean hydrogen and new energy society
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    • v.18 no.3
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    • pp.292-300
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    • 2007
  • A dynamic system model of a proton exchange membrane fuel cell(PEMFC) has been developed. The PEMFC of this study has large active area with water cooling in order to simulate the performance of the commercially viable PEMFC system for the transportation. A PEMFC stack model is a transient thermal model which is respond to the dynamic change of the coolant temperature and the flow rate. The dynamic cooling system model has been developed to determine the coolant flow rate and the coolant temperature. Prior to the system level study, thermal management criteria have been set up and brought to the control command of the cooling system. Since the system model is designed to evaluate the effect of thermal management on the system performance, it is attempted to determine the proper control algorithm of the cooling system so that the PEMFC system is working on the thermal management criteria. As a result of simulation, feedback controlled cooling system consumes less power and produce more power comparing with that of conventionally controlled cooling system.

Two Dimensional Numerical Model for Thermal Management of Proton Exchange Membrane Fuel Cell with Large Active Area (대면적 셀 고분자 막전해질 연료전지의 열관리를 위한 2 차원 수치 해석 모델)

  • Yu, Sang-Seok;Lee, Young-Duk;Ahn, Kook-Young
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.5
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    • pp.359-366
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    • 2008
  • A two-dimensional thermal model of proton exchange membrane fuel cell with large active area is developed to investigate the performance of fuel cell with large active area over various thermal management conditions. The core sub-models of the two-dimensional thermal model are one-dimensional agglomerate structure electrochemical reaction model, one-dimensional water transport model, and a two-dimensional heat transfer model. Prior to carrying out the simulation, this study is contributed to set up the operating temperature of the fuel cell with large active area which is a maximum temperature inside the fuel cell considering durability of membrane electrolyte. The simulation results show that the operating temperature of the fuel cell and temperature distribution inside the fuel cell can affect significantly the total net power at extreme conditions. Results also show that the parasitic losses of balance of plant component should be precisely controlled to produce the maximum system power with minimum parasitic loss of thermal management system.