• 설비공학논문집
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• 제5권1호
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• pp.44-54
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• 1993

This is an experimental study to identify the performance of air-to-air rotary heat exchanger with polyurethane foam matrix. The experimental apparatus including heating AHU(Air Handling Unit), cooling AHU, sensor chamber, and heat exchanger testing unit was designed and manufactured in this study. The performance of heat exchanger with porous polyurethane foam matrix was tested with variations of the density and the thickness of matrix, regulating the wind velocity and the rotational speed of matrix. The actual heat recovery effectiveness, air leakage rate, and pressure drop of heat exchanger were measured and analyzed.

• 설비공학논문집
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• 제18권12호
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• pp.992-998
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• 2006

This study is to optimize design parameters for waste heat recovery boiler with water tube and three drum. The design optimization considered here is to find the most economic dimension of the boiler considered which results in a minimum cost in producing a unit amount of steam per given period of operation. For this purpose, optimize design have to determine what are the main parameters of affecting the total cost of producing a unit amount of steam which is comprised of manufacturing cost of the boiler, operating cost of the fan etc.

• 한국해양환경ㆍ에너지학회지
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• 제14권4호
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• pp.301-306
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• 2011

저온 해수에너지를 이용한 난방사이클 및 이와 연계할 수 있는 적정 담수화사이클에 대하여 제안 및 해석을 수행하였다. 난방사이클은 기본 증기압축식 사이클을 이용하여 1단 및 2단압축사이클에 대해 해석을 수행하였고, 담수화사이클은 난방사이클과 연계할 수 있도록 설계하여 해석을 수행하였다. 난방사이클의 증발기 열원으로 5이하의 저온 해수열을 이용하였고, 난방수 온도는 60 이상 공급될 수 있도록 해석하였으며, 사이클 작동유체는 R-134a, R-1234 yf, R-600a를 적용하였다. 사이클 해석 결과, 2단압축사이클을 적용할 경우 1단압축사이클에 비해 모든 냉매에서 압축기 소요동력은 약 15.6% 감소하였고, 성능계수는 약 17.6% 향상되었다. 냉동법 담수화 사이클의 경우 R-134a에 대해서 난방수 60 조건일 때, 1단압축 사이클에 비해 2단압축사이클을 적용할 경우 담수 1kg 생산당 에너지가 약 19.8% 감소하는 것으로 나타났다.

• KIEAE Journal
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• 제4권3호
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• pp.203-210
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• 2004

This dissertation identifies and investigates the possible control modes of hybrid ventilation system in applying to general apartments. It evaluates range of hybrid ventilation control modes in terms of indoor air quality, thermal comfort, and energy consumption in a living room and a kitchen of the $1000m^2$ apartment. The TRNSYS simulation program was used for evaluating the following four ventilation types : A ventilation mode relying on only infiltration for supplying air, A natural ventilation mode considering with weather condition, A hybrid ventilation (natural + mechanical ventilation) mode allowing minimum ventilation with no heat exchange, and a hybrid ventilation mode with heat exchange. This study shows the following results. As temperature being controlled by heating cooling equipments, there is without significant difference in thermal performance among ventilation types. Regarding Indoor Air quality, Indoor air contamination level of the hybrid ventilation case consistently keep the lower levels. The hybrid ventilation modes consume more energy by a 49% as compared to the A ventilation mode relying on only infiltration for supplying air. It is caused by the continuous ventilation for keeping good indoor air quality; the increase of energy consumption can be attributable to the increase of the heating energy. Therefore, the heat exchange between indoor and outdoor air is required during heating season in severe weather conditions. During the cooling seasons, Introducing natural ventilation can achieve energy saving by 40 ~ 45%. Thus, it can be an effective strategies for energy saving. Based on these results, a hybrid ventilation system can be suggested as an effective ventilation strategy for archiving high level of indoor air quality, thermal comfort, and energy consumption.

• 한국건축시공학회지
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• 제20권4호
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• pp.339-345
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• 2020

본 연구는 매년 수만 건 발생되는 화재에서 화재확산에 의한 피해 예방과 대응 마련을 위해 공동주택 및 일반건물의 내부화재를 실물화재실험을 통해 재현하였다. 또한, 개구부 크기와 차양길이 조건을 달리하고 이에 따른 외벽온도 분포를 분석하여 화재확산방지 기초자료를 제공하고자 하였다. 실험결과, 차양을 설치하지 않았을 때 최고온도는 약 380℃ 이상으로 나타났다. 차양을 설치하지 않은 최고온도를 기준으로 차양길이가 150mm 일 때, 동일한 측정점에서 약 90℃가량 낮아졌으며, 300mm에서 약 150℃ 이상, 450mm에서 175℃ 이상 온도가 낮아졌으며, 차양길이 600mm 일 때, 최고온도 차는 약 180℃ 이상 낮아지는 것으로 나타나 개구부 상부의 차양 설치가 외벽의 수직화재 확산에 의한 화염온도를 낮추는데 효과가 있는 것으로 판단된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2165-2170
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• 2008

The cooling load in winter season is significant in many commercial buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. Therefore, the development of a multi-heat pump which can cover heating and cooling simultaneously for each indoor unit is required. In this study, the characteristics and performance of a simultaneous heating and cooling heat pump in the cooling-only and cooling-main operating mode was investigated experimentally with a variation of indoor air dry bulb temperature which is from $21^{\circ}C$ to $35^{\circ}C$. EEV opening was adjusted from 20% to 24% during the tests. When the indoor air temperature varied, the performance in the cooling-only mode was more sensitive to the temperature than in the cooling-main mode. The total capacity and COP were increased by 53.8% and 48.1%, respectively, in the cooling-main, while those were increased by 19.6% and 19.3% in the cooling-only mode. The performance differences between the two operating modes became larger at lower temperatures, especially for the COP.

• 설비공학논문집
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• 제20권7호
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• pp.492-499
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• 2008

The cooling load in winter is significant in many commercial buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. The development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the performance of a multi-heat pump with 3-piping system was investigated as a function of refrigerant charge and its performance was analyzed in cooling mode, heating mode, and heat recovery mode. COP in the heating or cooling mode showed little dependence on refrigerant charge at overcharge conditions, while those were strongly dependent on refrigerant charge at undercharge conditions and outdoor inlet temperature. In the heat recovery mode, the performance of the system was very sensitive to charge amount at all conditions. Optimum charge amount in the heat recovery mode was 14% lower than that in the cooling mode at the standard condition because the refrigerant only passed the indoor units. It is required to store the excessive refrigerant charge in a storage tank to optimize the system performance at operating modes.

• 대한건축학회논문집:계획계
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• 제34권7호
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• pp.21-29
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• 2018

This study aimed to find and suggest the purpose of future plans, critical items on designing and Related standards to amend construction standards for domestic energy saving and environmentally friendly housings. It would also activate and increase the supplies of passive house minimizing the problems on current apartment housings in winter and reducing heating energy which brings fine dust pollution. After defining the standard model of Korean apartment housings(reference model), this study calculated the amount of heating energy demand per unit area annually as applying the yearly changed standards from 2008 to 2017 to existing standard model. It turned out that applying 2017 construction standards of energy saving and eco-friendly housings to reference model has saved up to 75% of heating energy demand comparing to the one applied 2008's. However, it still could not solve the fundamental problems such as winter fungus, condensation, freezing, freeze and burst, and insulation weakness space, and could not be free from fine dust particles. To solve them, this study suggested improved standards adding critical items on design related to outside insulation, cut off the heat-bridge, enforce air-tightness and heat change efficiency on heat recovery ventilator. As a result, it has reduced more than 10% of heat demand from 2017. It would be more than 90% of savings from 2008 if we make the amount of heat loss be zero on heat bridge on designing stage in the future.

• 한국항공우주학회지
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• 제49권5호
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• pp.437-446
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• 2021

비행체의 속도가 빨라질수록, 비행 시 발생하는 공력 가열이 커진다. 고속 비행체의 속도가 빨라지면서 비행체의 외피는 수백 ℃까지 가열되기도 하며, 동시에 동체 내부의 전자장비들도 함께 가열되어 상대적으로 사용온도가 낮은 전자장비들의 열적 안전성이 위협받기 시작하였다. 이에 따라 개발 단계에서 전자장비의 온도 예측 및 외부시스템을 이용한 온도 조절 등 장비의 열적 안전성을 예측하고, 이를 확보하기 위한 다양한 시도가 있었다. 본 논문에서는 일회성 고속 비행체 내 장비의 열적 안전성을 예측할 수 있는 열 해석 모델을 구축하는 기술을 개발하였다. 장비 내부의 열전달 특성을 파악하기 위한 간단한 지상 모사실험을 수행하였고, 그 결과를 바탕으로 열전달 특성을 모사한 열 해석모델을 구축하였다. 이 기술을 활용하여 장비 열 해석 모델을 구축한다면, 비행 시장비 내부 구성품별 온도 변화를 예측할 수 있고, 더 나아가 열에 가장 취약한 특정 소자의 온도를 예측할 수 있기 때문에 더 정밀한 열적 안전성 예측이 가능하다.

• 한국응용과학기술학회지
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• 제36권4호
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• pp.1410-1419
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• 2019

본 연구는 한냉지에서 실외기에 서리가 형성되지 않는 난방이 가능한 히트펌프를 개발하고자 한다. 그래서 실내에서 -25℃의 환경을 제공할 수 있는 항온기 및 실험챔버를 구성하였다. 실험장치 내에 설치된 히트펌프의 실외기 전면에 도달하는 공기의 특성을 파악할 필요가 있어 범용소프트웨어인 ANSYS CFX를 이용하여 유동해석을 하였다. 그 결과 시뮬레이션 조건(5.0~7.0 m/s)의 모든 영역에서 실외기 전방에 도달하는 공기의 유속이 자연상태와 다르게 분포함을 파악하였다. 따라서 실외기 전면에 일정한 공기 유속이 도달할 수 있도록 별도의 공기분배기를 추가 설치할 필요가 있다고 판단된다.