• 제목/요약/키워드: cooling power load

검색결과 235건 처리시간 0.028초

반도체 공정용 칠러의 채널별 제어특성에 관한 실험적 연구 (Experimental Study on the Control Characteristics of Each Channel in a Semiconductor Chiller)

  • 김현중;권오경;차동안;김용찬
    • 대한기계학회논문집B
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    • 제35권12호
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    • pp.1285-1292
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    • 2011
  • 본 연구에서는 전자식 팽창밸브를 적용한 반도체 공정용 칠러에 관한 실험적 연구를 통해 시스템 특성을 파악하였다. 또한 온도 변화에 따른 신속한 대응을 할 수 있도록 온도상승 및 하강실험, 부하변화에 따른 온도영역별 제어정밀도 실험을 함으로써 각 제어 방식에 따른 운전 특성을 파악하였다. 온도상승 시 소비전력은 8.9 kW로 측정되었으며 CH1이 37.5분, CH2가 39.5분이 소요되었으며, 온도하강에는 총 26.5분이 소요되었다. 부분부하가 적용되는 경우 전부하가 적용되는 경우에 비해 제어정밀도의 변화폭이 큰 것으로 나타났으며 스텝모터 구동방식을 적용한 CH2의 제어정밀도가 상대적으로 우수한 것으로 나타났다. 냉각수를 이용한 냉각사이클 영역에서 소비전력은 1.8 kW로 냉동사이클을 적용한 방식에 비해 절반가량으로 감소된 것으로 나타났다. 본 연구는 실험결과를 바탕으로 반도체 공정용 칠러의 최적제어방안을 제시하였다.

반도체 클린룸용 증기가습 및 수분무가습 외기공조시스템의 에너지소비량 비교연구 (Comparative Study on Energy Consumption in Steam-Humidification- and Water-Spray-Humidification-Type Outdoor Air-Conditioning Systems for Semiconductor Manufacturing Clean Rooms)

  • 김형태;송근수;김기철;유경훈;손승우;신대건;박덕준;권오명
    • 대한기계학회논문집B
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    • 제35권12호
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    • pp.1249-1255
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    • 2011
  • 최근의 반도체 제조용 대규모 클린룸에서는 도입 외기를 가열가습 및 냉각감습하는 외기공조시스템의 에너지소비량이 클린룸 환경을 유지하기 위해 필요한 전체 공조에너지의 약 45 %를 차지하고 있다. 특히 동기(겨울철)의 경우 외기를 가습하기 위한 에너지소비량은 매우 높다. 따라서 에너지절감을 통한 제조비용 절감 및 온실가스 감축을 위해 외기부하와 관계되는 공조에너지의 사용효율 증대 및 철저한 사용합리화가 요구되고 있다. 따라서 반도체 클린룸용 외기공조시스템의 핵심 가습방식인 증기가습과 수분무가습 방식에 대한 소비전력량을 분석하는 것은 에너지절약적 측면에서 상당히 가치가 있다고 판단된다. 본 연구에서는 전극봉식 가습기에 의한 증기가습방식 및 에어와셔에 의한 수분무가습방식 외기공조시스템들의 공조프로세스 및 소비전력량을 외기량 1000 $m^3$/h의 경우 기흥지역의 동기 및 하기의 피크부하에 대해 비교하는 실험을 수행하였다. 실험결과들로부터 에어와셔 수분무가습 외기공조시스템이 전극봉식 증기가습 외기공조시스템보다 연간 소비전력량이 적어서 에너지절약적임을 보여주었다.

용융탄산염 연료전지 스택 온도 조절을 위한 분리판에 관한 수치 해석 연구 (Numerical Studies of a Separator for Stack Temperature Control in a Molten Carbonate Fuel Cell)

  • 김도형;김범주;임희천
    • 한국수소및신에너지학회논문집
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    • 제22권3호
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    • pp.305-312
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    • 2011
  • The use of a separator to control stack temperature in a molten carbonate fuel cell was studied by numerical simulation using a computational fluid dynamics code. The stack model assumed steady-state and constant-load operation of a co-flow stack with an external reformer at atmospheric pressure. Representing a conventional cell type, separators with two flow paths, one each for the anode and cathode gas, were simulated under conditions in which the cathode gas was composed of either air and carbon dioxide (case I) or oxygen and carbon dioxide (case II). The results showed that the average cell potential in case II was higher than that in case I due to the higher partial pressures of oxygen and carbon dioxide in the cathode gas. This result indicates that the amount of heat released during the electrochemical reactions was less for case II than for case I under the same load. However, simulated results showed that the maximum stack temperature in case I was lower than that in case II due to a reduction in the total flow rate of the cathode gas. To control the stack temperature and retain a high cell potential, we proposed the use of a separator with three flow paths (case III); two flow paths for the electrodes and a path in the center of the separator for the flow of nitrogen for cooling. The simulated results for case III showed that the average cell potential was similar to that in case II, indicating that the amount of heat released in the stack was similar to that in case II, and that the maximum stack temperature was the lowest of the three cases due to the nitrogen gas flow in the center of the separator. In summary, the simulated results showed that the use of a separator with three flow paths enabled temperature control in a co-flow stack with an external reformer at atmospheric pressure.

풍력 터빈용 750 kW 급 고온초전도 발전기 모듈의 코일 구조 설계 및 열 해석 (Structural Design and Thermal Analysis of a Module Coil for a 750 kW-Class High Temperature Superconducting Generator for Wind Turbine)

  • 투덴수런 오운자르갈;고병수;성해진;박민원
    • 한국산업정보학회논문지
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    • 제24권2호
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    • pp.33-40
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    • 2019
  • 많은 풍력회사들은 큰 용량, 작은 크기 및 가벼운 무게의 풍력 발전기를 개발하기 위해 노력해 왔다. 고온초전도 풍력발전기는 기존의 풍력 발전기에 비해 부피와 중량을 줄일 수 있기 때문에 풍력 발전시스템에 더 적합하다. 그러나 고온초전도 발전기는 큰 진공 용기 및 계자 코일의 유지 보수가 어려운 문제를 가지고 있다. 이러한 문제는 고온초전도 계자 코일의 모듈화를 통해 해소될 수 있다. 그런데 고온초전도 모듈 코일에는 직류 전류를 전달하기 위한 전류 리드가 필요하며, 이는 큰 열전달 부하를 발생시킨다. 따라서 전류 리드는 전도 및 Joule 열 부하를 줄이기 위해 최적으로 설계되어야 한다. 본 논문에서는 750 kW급 고온초전도 발전기에 대한 모듈 코일의 구조 설계 및 열 해석을 다루었다. 모듈 코일의 전도 및 복사열 해석은 3D 유한요소법 프로그램을 사용하여 분석하였으며, 그 결과 총 열부하는 극저온 냉각장치의 냉각 용량보다 작았다. 본 논문에서 제시한 설계 및 해석결과는 풍력 발전시스템의 초전도 발전기 개발에 효과적으로 활용할 수 있을 것이다.

설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제26권12호
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. 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 fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (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 for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

공기조화, 냉동 분야의 최근 연구 동향 - 1998년 1999년 학회지 논문에 대한 종합적 고찰 - (Recent Progress in Air Conditioning and Refrigeration Research - A Review of papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 1998 and 1999 -)

  • 이재헌;김광우;김병주;이재효;김우승;조형희;김민수
    • 설비공학논문집
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    • 제12권12호
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    • pp.1098-1125
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    • 2000
  • A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 1998 and 1999 has been done. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environment. The conclusions are as follows. 1) A review of the recent studies on fluid flow, turbomachinery and pipe-network shows that many experimental investigations are conducted in applications of impingement jets. Researches on turbulent flows, pipe flows, pipe-networks are focused on analyses of practical systems and prediction of system performance. The results of noise reduction in the turbomachinery are also reported. 2) A review of the recent studies on heat transfer analysis and heat exchanger shows that there were many papers on the channel flow with the application to the design of heat exchanger in the heat transfer analysis. Various experimental and numerical papers on heat exchanger were also published, however, there were few papers available for the analysis of whole system including heat exchanger. 3) A review of the recent studies on heat pump system have focused on the multi-type system and the heat pump cycle to utilize treated sewage as the heat source. The defrosting and the frosting behaviors in the fin-tube heat exchanger is experimentally examined by several authors. Several papers on the ice storage cooling system are presented to show the dynamic simulation program and optimal operation conditions. The study on the micro heat pipes for the cooling of high power electronic components is carried out to examine the characteristics of heat and mass transfer processed. In addition to these, new type of separate thermosyphon is studied experimentally. 4) The recent studies on refrigeration/air conditioning system have focused on the system performance and efficiency for new alternative refrigerants. New systems operating with natural refrigerants are drawing lots of attention. In addition to these, evaporation and condensation heat transfer characteristics of traditional and new refrigerants are investigated for plain tubes and also for microfin tubes. Capillary tubes and orifice are main topics of research as expansion devices and studies on thermophysical properties of new refrigerants and refrigerant/oil mixtures are widely carried out. 5) A review of the recent studies on absorption cooling system shows that numerous experimental and analytical studies on the improvement of absorber performance have been presented. Dynamic analysis of compressor have been performed to understand its vibration characteristics. However research works on tow-phase flow and heat transfer, which could be encountered in the refrigeration system and various phase-change heat exchanger, were seemed to be insufficient. 6) A review of recent studies on duct system shows that the methods for circuit analysis, and flow balancing have been presented. Researches on ventilation are focused on the measurement of ventilation efficiency, and variation of ventilation efficiency with ventilation methods by numerous experimental and numerical studies. Furthermore, many studies have been conducted in real building in order to estimate indoor thermal environments. Many research works to get some information for cooling tower design have been performed but are insufficient. 7) A review on the recent studies on architectural thermal environment and building mechanical systems design shows that thermal comfort analysis is sitting environment, thermal performance analysis of Korean traditional building structures., and evaluation of building environmental load have been performed. However research works to improve the performance of mechanical system design and construction technology were seemed to be insufficient.

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자동차용 연료전지 시스템의 가습모델과 열/물균형 유지방법 (Humidification model and heat/water balancing method of PEMFC system for automotive applications)

  • 정승훈;윤석호;김민수
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2005년도 춘계학술대회
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    • pp.339-344
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    • 2005
  • A PEMFC system model for FCEV was constructed and simulated numerically to examine the heat/water flow of the system and air/fuel humidification process for various operation conditions (ambient pressure /temperature/humidity, operating temperature, power load). We modeled PEMFC stack which can generate maximum electricity of about 80 kW. This stack consists of 400 unit cells and each unit cell has $250cm^2$ reacting area. Uniform current density and uniform operating voltage per each cell was assumed. The results show the flow characteristics of heat and water at each component of PEMFC system in macro-scale. The capacity shortage of the radiator occurred when the ambient was hot $(over\;40^{\circ}C)$ and power level was high (over 50 kW). In spite of some heat release by evaporation of water in stack, heat unbalance reached to 20kW approximately in such a severe operating condition. This heat unbalance could be recovered by auxiliary radiators or high speed cooling fan with additional cost. In cold environment, the capacity of radiator exceeded the net heat generation to be released, which may cause a problem to drop the operating temperature of stack. We dealt with this problem by regulating mass flow rate of coolant and radiator fan speed. Finally, water balance was not easily broken when we retrieved condensed and/or unused water.

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고분자 전해질 연료전지를 이용한 무인비행체 동력시스템 설계 (Power System Development of Unmanned Aerial Vehicle using Proton Exchange Membrane Fuel Cell)

  • 지영광;손영준;박구곤;김창수;최유송;조성백
    • 한국수소및신에너지학회논문집
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    • 제23권3호
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    • pp.250-255
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    • 2012
  • In this paper, the development and performance analysis of a fuel cell-powered unmanned aerial vehicle is described. A fuel cell system featuring 1 kW proton exchange membrane fuel cell combined with a highly pressurized fuel supply system is proposed. For the higher fuel consumption efficiency and simplification of overall system, dead-end type operation is chosen and each individual system such as purge system, fuel supply system, cooling system is developed. Considering that fluctuation of exterior load makes it hard to stabilize fuel cell performance, the power management system is designed using a fuel cell and lithium-ion battery hybrid system. After integration of individual system, the performance of unmanned aerial vehicle is analyzed using data from flight and laboratory test. In the result, overall system was properly operated but for more duration of flight, research on weight lighting and improvement of fuel efficiency is needed to be progressed.

소형 4행정사이클 무과급 디이젤 기관의 성능 시뮤레이션 전산프로그램의 개발에 관한 연구 (A study on the development of simulation program for the small naturally aspirated four-stroke diesel engine)

  • 백태주;전효중
    • Journal of Advanced Marine Engineering and Technology
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    • 제8권1호
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    • pp.17-36
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    • 1984
  • Since 1973, the competition on the development of fuel saving type internal combustion engines has become severe by the two times oil shock, and new type engines are reported every several months. Whenever these new type engines are developed, new designs are required and they will be offered in the market after performing the endurance test for a long time. But the engine market is faced with a heavy burden of finance, as the developing of a new engine requires tremendous expenses. For this reason, the computer simulation method has been lately developed to cope with it. The computer simulation method can be available to perform the reasonable research works by the theoretical analysis before carrying out practical experiments. With these processes, the developing expenses are cut down and the period of development is curtailed. The object of this study is the development of simulation computer program for the small naturally aspirated four-stroke diesel engine which is intended to product by the original design of our country. The process of simulation is firstly investigated for the ideal engine cycle, and secondly for the real engine cycle. In the ideal engine cycle, each step of the cycle is simulated by the energy balance according to the first law of thermodynamics, and then the engine performance is calculated. In the real cycle imulation program, the injection rate, the preparation rate and the combustion rate of fuel and the heat transfer through the wall of combustion chamber are considered. In this case, the injection rate is supposed as constant through the crank angle interval of injection and the combustion rate is calculated by the Whitehouse-Way equation and the heat transfer is calculated by the Annand's equation. The simulated values are compared with measured values of the YANMAR NS90(C) engine and Mitsubishi 4D30 engine, and the following conclusions are drawn. 1. The heat loss by the exhaust gas is well agree with each other in the lower load, but the measured value is greater than the calculated value in the higher load. The maximum error rate is about 15% in the full load. 2. The calculated quantity of heat transfer to the cooling water is greater than the measured value. The maximum error rate is about 11.8%. 3. The mean effective pressure, the fuel consumption, the power and the torque are well agree with each other. The maximum error is occurred in the fuel consumption, and its error rate is about 7%. From the above remarks, it may be concluded that the prediction of the engine performance is possibly by using the developed program, although the program needs to reform by adding the simulation of intake and exhaust process and assumping more reliable mechanical efficiency, volumetric efficiency, preparation rate and combustion rate.

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고밀도 폴리에틸렌 융착부에 대한 단기간 파손 평가법 개발 - 한계하중 적용 - (Development of a Short-term Failure Assessment of High Density Polyethylene Pipe Welds - Application of the Limit Load Analysis -)

  • 류호완;한재준;김윤재;김종성;김정현;장창희
    • 대한기계학회논문집A
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    • 제39권4호
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    • pp.405-413
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    • 2015
  • 최근 미국에서는 가동기간이 오래된 원전 매설배관에서 부식 및 침식에 의해 삼중수소 누설로 지하수가 오염되는 사례가 급증하고 있다. 따라서, 현재 원전 안전등급 매설배관으로 사용되고 있는 금속재료의 배관을 대신해서 부식 및 침식 등의 열화 손상에 대한 저항성이 우수한 고밀도 폴리에틸렌(HDPE) 배관을 ASME Code Class 3 안전계통 배관으로 사용하기 위한 연구가 수행되고 있다. 본 연구에서는 발전소 가동 중 매설배관에 가해질 수 있는 하중과 온도 범위를 바탕으로 HDPE 배관 융착부에 대한 인장 시험과 저속균열성장 (SCG) 시험을 수행하였다. 시험 결과로 얻은 SCG 시험편의 파단면을 분석하여 HDPE 재료의 파손 기구를 파악하였다. 이를 바탕으로 3D 유한요소 해석을 이용하여 균열이 있는 HDPE 재료가 버틸 수 있는 한계하중에 대한 검증을 수행하였다.