• Title/Summary/Keyword: Stack cooler

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A Study on the Stack Temperature Profile of a Standing Wave Thermoacoustic Cooler (정재파 열음향 냉각기의 스택 온도구배에 대한 연구)

  • Paek, In-Su
    • The Journal of the Acoustical Society of Korea
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    • v.28 no.1
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    • pp.19-24
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    • 2009
  • Investigations of the relation between the stack temperature profile of a standing wave thermoacoustic cooler and the cooling efficiency were performed. Based on the mathematical derivations using the Rott Equation, it was found that the temperature profile along the stack becomes nonlinear as the enthalpy flux passing through the stack increases. It was also found that such nonlinear temperature profiles lower the cooling efficiency. Simulations using a thermoacoustic simulation program called DELTAE showed that the nonlinear temperature profile occurs with a long stack and large cooling load.

Effects of Pitch Length of Stack-type EGR Cooler on Heat Exchange Characteristics in a Diesel Engine (적층형 EGR Cooler의 Pitch 길이 변화가 열교환 특성에 미치는 영향)

  • Hwang, Se-Joon;Kim, Min-Chol;Jang, Sang-Hoon;Kim, Hyung-Man
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.2
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    • pp.135-140
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    • 2010
  • An important goal in diesel engine research is the development of a means to reduce the emissions of nitrogen oxides (NOX). The use of a cooled exhaust gas recirculation (EGR) system is one of the most effective techniques currently available for reducing nitrogen oxides. Since Particular Matter (PM) fouling reduces the efficiency of an EGR cooler, a trade-off exists between the amount of NOX and PM emissions, especially at high engine loads. In the present study, engine dynamometer experiments have been performed to investigate the heat exchange characteristics of the stack-type EGR coolers with wave fin pitches of 3.6 and 4.6 mm. The results show that the heat exchange effectiveness is decreased as surface area decrease with pitch of 4.6 mm due to PM fouling. As surface area increase at pitch of 3.6 mm, super-cooling happens in the recirculated exhaust gas.

Experimental Studies on the Stack Cooling Performance Using a $CO_2$ Air Conditioning System in Fuel Cell Vehicles (이산화탄소 에어컨 시스템을 이용한 연료전지 자동차의 스택 냉각성능에 대한 실험적 연구)

  • Kim, Sung-Chul;Kim, Min-Soo;Won, Jong-Phil
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.3
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    • pp.87-93
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    • 2008
  • The $CO_2$ air conditioning system installed in fuel cell vehicles could be used either for stack cooling or for cabin cooling, and thus was used for the stack cooling when additional stack heat release was required over a fixed radiator capacity for high power generation. This study investigated the performance of the stack cooling system using $CO_2$ air conditioner at various operating conditions. Also, the heat releasing effectiveness and mutual interference were analyzed for the stack cooling system using an air conditioner and compared with the conventional radiator cooling system with/without cabin cooling. The heat release of the stack cooling system with the aid of $CO_2$ air conditioner increased up to 36% more than that of the conventional radiator cooling system with cabin cooling. Furthermore, the heat release of the stack cooling system using $CO_2$ air conditioner increased more by 7% than that of the conventional radiator cooling system without cabin cooling.

Design of a Heat Release System for Fuel Cell Vehicles (연료전지 자동차 열방출 시스템의 설계)

  • Kim, Sung-Chul;Park, Min-Su;Jung, Seung-Hun;Yoon, Seok-Ho;Kim, Min-Soo
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.11a
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    • pp.545-548
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    • 2005
  • There is a close relation between the heat generation in the fuel cell stack and the fuel cell performance. In PEM fuel Gell vehicles, the stack coolant temperature is about $65^{\circ}C$, which is far lower than that for general automobile engine. Therefore, it is hard to release heat generated in the stack by using a radiator of limited size because of the reduced temperature difference between the coolant and the ambient air. In this study, indirect stack cooling system using $CO_2$ heat pump was designed and its stack cooling performance in releasing heat to the ambient was investigated. This work focuses on a series of processes that grasp the relation among the fuel cell power, the radiator capacity and the stack temperature. The purpose of this work is to find out a way to properly release sufficient amount of heat through the finite sized radiator, so that the stack power general ion can not be deteriorated due to the stack temperature increase. The optimization between the compressor power consumption and the fuel cel1 output power can be carried out to maximize the performance of fuel cell system.

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Design of a Heat Release System for Fuel Cell Vehicles (연료전지 자동차 열방출 시스템의 설계)

  • Kim, Min-Soo;Kim, Sung-Chul;Park, Min-Su;Jung, Seung-Hun;Yoon, Seok-Ho
    • New & Renewable Energy
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    • v.1 no.4 s.4
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    • pp.49-54
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    • 2005
  • There is close relation between the heat generation in the fuel cell stack and the fuel performance. In PEM fuel cell vehicles, the stack coolant temperature is about $65^{\circ}C$, which is far lower than that for general automobile engine. Therefore, it is hard to release heat generated in the stack by using a radiator of limited size because of the reduced temperature difference between the coolant and the ambient air. In this study, indirect stack cooling system using $CO_2$ heat pump was designed and its stack cooling performance in releasing heat to the ambient was investigated. This work focuses on a series of processes that grasp the relation among the fuel cell power, the radiator capacity and the stack temperature. The purpose of this work is to find out a way to properly release sufficient amount of heat through the finite sized radiator, so that the slack power generation can not be deteriorated due to the stack temperature increase. The optimization between the compressor power consumption and the fuel cell output power can be carried out to maximize the performance of fuel cell system.

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Dynamic Analysis of PEM fuel cell system (PEM 연료전지시스템의 동특성 해석)

  • Kim Beomsoo;Jeon Soonil;Lim Wonsik;Park Yeong-il
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.353-356
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    • 2005
  • We developed a dynamic model of PEM fuel cell system which can analyze its transient response to dynamic load current. System components such as compressor, air cooler, humidifier, and stack were modeled based on their dynamic equations and performance maps by using Matlab Simulink platform. Through this simulation model, dynamic characteristics of fuel cell system including oxygen excess rat io, stack voltage, and system efficiency were shown. In addition to that, we briefly analyzed the humidity effect on cathode pressure and system efficiency, expecting that this model can be further used to optimize fuel cell system parameters just like operating pressure and temperature, humidity and oxygen excess ratio.

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Design of a 20 Tons/Day Gasification Test Bed (20톤/일급 가스화공정 Test Bed 설계)

  • Chung, Jaehwa;Seo, Seokbin;Seo, Haikyung;Chi, Junhwa
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.112.1-112.1
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    • 2010
  • To develop domestic IGCC gasification technology, a gasification test bed with a capacity of 20 tons/day has been designed. The main components of the test bed designed are a coal pulverizing and feeding facility, a gasifier, a syngas cooler, a gas treatment unit, oxygen and nitrogen tanks, and flare stack. For wide applications to the development of advanced coal gasification technology, many special functions have been given to it such as syngas recirculation, char recirculation, and multiple stage gasification. The test bed will be used for testing the characteristics of various types of coals, deriving optimum conditions for efficient gasifier operation and trouble shooting for the Korea IGCC demonstration plant. It will also be applied as a useful tool to develop scale-up design technology of IGCC and proceed to commercialization.

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Analysis of Performance and Energy Saving of a SOFC-Based Hybrid Desiccant Cooling System (건물용 연료전지 기반 하이브리드 제습냉방시스템 성능 및 에너지 절감 분석)

  • IN, JUNGHYUN;LEE, YULHO;KANG, SANGGYU;PARK, SUNGJIN
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.2
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    • pp.136-146
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    • 2019
  • A solid oxide fuel cell (SOFC) based hybrid desiccant cooling system model is developed to study the effect of fuel utilization rate of the SOFC on the reduction of energy consumption and $CO_2$ emission. The SOFC-based hybrid desiccant cooling system consists of an SOFC system and a Hybrid desiccant cooling system (HDCS). The SOFC system includes a stack and balance of plant (BOP), and HDCS. The HDCS consists of desiccant rotor, indirect evaporative cooler, electric heat pump (EHP), and heat exchangers. In this study, using energy load data of a commercial office building and SOFC-based HDCS model, the amount of ton of oil equivalent (TOE) and ton of $CO_2$ ($tCO_2$) are calculated and compared with the TOE and $tCO_2$ generation of the EHP using grid electricity.

A Study on the Fluoro-polymer Composite Coatings for Protecting the Corrosion of Fossil-fuel Power Plants

  • Kang, Min Soo;Lee, Byung Seung;Chang, Hyun Young;Jin, Tae Eun;So, Il Soo
    • Corrosion Science and Technology
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    • v.6 no.2
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    • pp.62-67
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    • 2007
  • Several heavy duty coatings at an every kind industry facilities to various systems currently have been applied review to the many industry fields. Corrosion-protective characteristics in the case of novolac epoxy among them and unsaturated polyester have been applied most widely. epoxy and flake heavy duty coatings are applied for such reason in an every kind facilities(stack, FGD, cooler, chemical tank etc) of a fossil-fuel power plants Cases of the fossil-fuel power plants are exposed to more severe corrosion environment compared with other facilities and It is difficult to display the performance of long-term method at apply to be the partial. Our study shows fluoro-polymer composite coating method to overcome of the limit. The comparison did previous method and heavy duty coating about FGD plants most at a corrosion environment among fossil-fuel power plants. Additionally, other facilities examined different heavy duty method. The design mode of fluoro-polymer composite coating according to an every kind facilities show extensive methods that are characteristic revelation of film(top, middle and primer layer) composition of the paint, film thickness in accordance with a facilities corrosion and the corrosion protective effectiveness to come into being use fluoro-polymer composite with heavy duty paint(epoxy).

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.