• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.250-253
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• 2007

The purpose of this research is focussed on the numerical predictions of the heat and smoke propagations for a passenger train fire in an underground subway tunnel for different air supply and extraction flowrates. The analysis is performed for one of the stations on subway line #5 in Seoul under the emergency operation mode for different air supply and extraction flowrates. Five different the air supply and extraction flowrates are considered for the numerical analyses. The numerical results show that the air supply and extraction flowrates affect the smoke control performance significantly by improving the smoke removal performance for the balanced control of air supply and smoke extraction and for the unbalanced control with lager smoke extraction than air supply.

• 한국태양에너지학회 논문집
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• 제25권2호
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• pp.63-69
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• 2005

This study is the survey of a transition procedure of building services systems(heat source, HVAC, water supply) through the survey of existing office buildings, building design documents. The preference & major consideration of system selection is the engineer's opinions. The results of this survey can be used in selection of building services system design. In this survey, "Hot & cold water generator system" and "single duct CAV+FCU system", "Elevated water tank system" are selected. The most important consideration in system selection is the energy saving in heat source system, and comfort in HVAC system, and water pressure in water supply system. They prefer "steam boiler+absorption chiller system" for heat source system, "steam boiler+ice thermal storage system", "hot & cold water generator system", "district heating+absorption chiller system" : "single duct CAV+FCU system" and "single duct VAV+convector system" for HVAC system: and "booster pump system" for water supply system.

• 설비공학논문집
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• 제26권5호
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• pp.218-223
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• 2014

Korea District heating corp. recently give an attention to combine the district heating and supply pipes as a two pipe system that are in the present system separated with room heating and warm water supply pipe, and the two pipe system is commonly applied for heating service in European countries. In the new two pipe system, only one heat source is supplied to a house and partitioned into room heating and warm water supply by household substation. So the effective distribution of supplied heat source in accordance to user intention is very important. This paper presents the development and performance test of three-way proportional control valve for a combined heat source system in district heating. The proposed valve is controlled to partition heat source into two different directions : hot water distributor for space heating and household substation for warm water supply in response to the pressure drops of tap water caused by the user. The performance investigation is shown within 3% of error compared to the theoretical model of the three-way proportional valve and its controllability is verified.

• 한국산학기술학회논문지
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• 제15권7호
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• pp.4047-4051
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• 2014

현대의 공동 주택은 에너지 효율을 높이기 위해 고기밀, 고단열 방식으로 지어지고 있는데 이러할 경우 환기량 부족에 따른 각종 부작용이 발생을 한다. 본 연구에서는 우리나라의 겨울철 대표적인 난방원으로 사용되고 있는 온돌시스템을 기본으로 구성하고 환기방법에 따른 실내 열환경을 평가하여 환기 방식에 따른 에너지 절감 요인을 분석하였다. 실험장치는 일정한 외기 조건을 모사하기 위해 항온항습 챔버에 뜬바닥 온돌 시스템을 설치하고 온돌시스템의 외기온도/습도 조건은 3조건($10^{\circ}C$/50%Rh, $0^{\circ}C$/-, $-10^{\circ}C$,-)으로 설정 하였다. 공급되는 온수온도는 2 조건($60^{\circ}C$, $50^{\circ}C$) 설정하여 설정된 환기 방식에 따라 성능시험을 수행 하여 열 환경 및 에너지 절감 요인을 비교 분석 하였다. 실험결과 급기온도는 온수온도가 높을수록 급기풍량이 적을수록 높았으며 바닥 급/배기 > 전열교환 급/배기 > 강제 급/배기 순으로 나타났다. 본 연구를 통해 다양한 환기 방식의 적용 가능성에 대하여 검토 할 수 있었다.

• 상하수도학회지
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• 제37권6호
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• pp.447-456
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• 2023

Risk assessment on Jeju Special Self-Governing Province(JSSGP)'s water supply facilities and establishment of adaptation measures for climate crisis factors were implemented. JSSGP's vulnerability to the climate crisis was high in the order of drought, heat wave, heavy rain and strong wind. As a drought adaptation measure, policies of water saving and revenue water ratio improvement were considered. As for the heat wave adaptation measure, the introduction of an advanced water treatment process was suggested in response to the increase of algae cell number which resulting in taste and odor problem. As for heavy rain adaptation measures, the installation and operation of automatic coagulant injection devices for water purification plants that take turbid surface water were proposed. As a measure to adapt to strong winds, stabilization of power supply such as installation of dual power line was proposed in preparation for power outages. It is expected that water facilities will be able to supply high-quality tap water to customers even under extreme climate conditions without interruption through risk assessment for climate crisis factors and active implementation of adaptation measures.

• 한국태양에너지학회 논문집
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• 제32권5호
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• pp.59-67
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• 2012

In this study,the compact type solar thermal and ground coupled heat pump hybrid system for space heating/cooling and hot water supply has been developed. This hybrid system was installed in Zero Energy Solar House(ZeSH) in KIER for the demonstration. The thermal performance and operational characteristics of this hybrid system were analysed especially. The results are as follows. (1) This hybrid system was designed in order to address the existing disadvantages of solar thermal/ground coupled heat pump system. For this design, all parts except solar collector and ground coupled heat pump were integrated into a single product in a factory. The compact type unit includes two buffer tanks, an expansion tank, pumps, valves, a controller, etc. This system has an advantage of easy installation with simple plumbing work even in narrow space. (2) The thermal charging and discharging time of the buffer tanks and its characteristics by ground coupled heat pump, and heat pump COP according to geo-source temperature and buffer storage temperature have been studied. This system was found to meet well to the heat load without any other auxiliary heating equipment. (3) The operating hours of the ground coupled heat pump as a backup device of solar thermal can be reduced significantly by using solar heat. It was also found that the minimum heating water supply setting temperature and maximum cooling water supply setting temperature make an influence on the heat pump COP. The lower heating water and the higher cooling water temperature, the higher COP. In this respect, the hybrid system's performance can be improved in ZeSH than conventional house.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.204-209
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• 2002

A PDP(Plasma Display Panel) module consists of a discharge panel, a SMPS(Switched Mode Power Supply) for power supply, driving boards for panel control, and a logic board. Driving boards supply high voltage pulses to induce glow discharge in the PDP panel. The electrical pulses excite the circuit elements and subsequently generate acoustic noises. The main sources of the noise in the circuit are the transformer of SMPS and the power MOSFET(Metal Oxide Semiconductor Field Effect Transistor) of driving boards, and the heat sinks often amplify the noise level. The reduction of the acoustic noises was achieved by modifying both the structural and circuit elements. The structural method was executed by the improvement of heat sinks. The optimization of SMPS and condensers was carried out for the circuit elements.

• 대한안전경영과학회지
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• 제16권2호
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• pp.167-174
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• 2014

Heating and air conditioning system is changing rapidly from the traditional HVAC central supply system to the individual supply system with electrical heat pump system (EHP) in Korean school buildings. The individual supply system has advantages to turn on and off individually and to adjust the thermal comfort separately, but energy is wasted in the unoccupied classroom when the last leaving occupant does not turn off the controller. If the controller is to be off automatically while the classroom is not in use, energy consumption would decrease dramatically. This project aims to cease the unnecessary EHP supply in vacant classroom by inputting the class schedule from the central control room to reduce the energy-spending. Experimental measurements were carried out between the controlled classroom that is turned off when not in use and the uncontrolled room that is turned on continually. Occupant's comfort and energy consumption were measured and compared between the controlled case and the uncontrolled case. The energy consumption of controlled classroom case is 30-60% less than that of the uncontrolled classroom case. This result shows that controlling the cooling supply for the unoccupied classroom using the class schedule can decrease the energy consumption remarkably. This supply control system can be used to conserve energy in school structures like universities.

• 전기학회논문지
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• 제64권11호
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• pp.1626-1630
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• 2015

This paper reflected the Temperature test value and compare the Computational Fluid Dynamic analysis value on particular characteristics of the multi-winding transformer's cooling apparatus equipped by heat pipe with excellent heat transfer ability on design Particularly if you look at multi-winding transformers that supply high-quality Direct current power to silicon production apparatus, heat generation due to high current supply is excessive thus, an innovative cooling apparatus is required in particular for reduced size transformer.

• 설비공학논문집
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• 제19권1호
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• pp.77-85
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• 2007

One of the most common approaches to achieve better thermal comfort with the radiant floor heating system is supply water temperature control, which is that supply water temperature is varied with outdoor air temperature. But the application of this control method was not easy, because there has been no way to determine the supply water temperature. So in this study, a comprehensive, yet simple calculation method to find out the required supply water temperature is suggested by combining the building heat loss equation and the heat emission model of hydronic radiant floor heating system for single zone. And then using this calculation method, the multizone control method is suggested and confirmed through the thermal simulation. It is shown that indoor air temperature is stably maintained around the set point.