• 한국산업융합학회 논문집
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• 제18권1호
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• pp.18-29
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• 2015

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The system was introduced into a real building and was examined by the field measurement. Judging from the measurements during three years(1999~2001), the state of the system operation was very stable through this period and it was clear that the system contributes to reduction of energy consumption for air-conditioning. Futhermore, a simulation model used the simple heat diffusion equation was developed to simulate its thermal characteristics and performances. The simulations resulted in air temperature in good agreement with the measurements. Also, from the result of numerical analysis, it is clear that the amount of heat supply by using this system is more than the amount of energy loss to the room above it. Therefore, it is concluded that this systems is very useful and the proposed numerical model can be used for the prediction of system thermal performance.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.133-137
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• 2011

Low-e glazing is classified as soft low-e glazing and hard low-e glazing. Hard low-e glazing can be temperable and its handling is comfortable because its coating film is a oxide film generated at high temperatures. But there is a fatal weakness that its insulation performance and shielding performance are lower compared to soft low-e glazing by low electrical conductivity of coating film. Soft low-e glazing is excellent because its coating film consists of Ag that is excellent electrical conductivity and it has strength that can supply various product consumers want. But soft low-e glazing has weaknesses that temperable and handling are difficult because Ag is oxidized easily. Therefore this study analyzes thermal performance of glazing by changing filling gas according to applying low-e glazing through simulation to judge performance before making sample. After this process, a comparative experimental study was done through TVS by making temperable low-e glazing.

• 한국태양에너지학회 논문집
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• 제27권4호
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• pp.19-26
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• 2007

This paper concerns the study of absorption refrigeration and heat pump cycle to use sewage. Simulation analysis on the double-effect absorption refrigeration cycle with parallel and two-stage heat pump cycle has been performed. The working fluid is Lithium Bromide and water solution. The absorption refrigeration cycle use sewage as a cooling water for the absorber and condenser, and absorption refrigeration cycle does that as a chilled water for the evaporator of the first stage cycle. And the two-stage cycle consists of coupling double-effect with parallel and single effect cycle so that the first stage absorber and condenser produces heating water to evaporate refrigerant in the evaporator of the second stage. The effects of operating variables such as a absorber temperature on the coefficient of performance have been studied for absorption refrigeration and heat pump cycle.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.807-812
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• 2008

The various attempts is made to solve the energy and environment problems. In addition, people interested in their life quality want the more eco-friendly living space. So we suggested that the earth-sheltered house could be one of the eco-friendly and low energy consuming houses to meet the social interest. And we also made data for design of the earth-sheltered house to be applicable to climate of Korea. In this study, a simulation was performed to estimate a boundary temperature according to earth sheltering thickness at the earth-sheltered part(exterior wall) in the case of earth sheltering on the plane ground not using a sloped site. And we analyzed the reduction of a thermal load by using this boundary temperature. We also compared a case of earth sheltering at the vertical wall with a case of earth sheltering at the roof to know the thermal reduction effect of a case of earth sheltering at the vertical wall.

• 설비공학논문집
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• 제29권3호
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• pp.105-110
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• 2017

Underfloor air distribution (UFAD) is an air distribution strategy for providing ventilation and space conditioning in buildings. UFAD systems use the underfloor plenum beneath a raised access floor to provide conditioned air through floor diffusers that create a vertical thermal stratification during cooling operations. Thermal stratification has significant effects on energy, indoor air quality, and thermal comfort performance. The purpose of this study was to characterize the influence of a linear bar grille diffuser on thermal stratification in both interior and perimeter zones by developing Gamma-Phi based prediction models. Forty-eight simulations were carried out using a Computational Fluid Dynamics (CFD) technique. The number of diffusers, the air flow supply, internal heat gains, and solar radiations varied among the different cases. Models to predict temperature stratification for the tested linear bar grille diffuser have been developed, which can be directly implemented into dynamic whole-building simulation software such as EnergyPlus.

• 전기학회논문지P
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• 제61권4호
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• pp.180-185
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• 2012

Tidal power is one of new and renewable energy sources. The seawater is stored inside a tidal embankment built at the mouth of a river or bay, where tides ebb and flow. The water turbine-generators produce power by exploiting the gap in the water level between the water outside and inside the embankment. Tidal power plant is a large plant that is installed on the sea. And then, the facility's operations and a separate control system for monitoring and maintenance is required. However, this plant predictive control of building systems and technologies have been avoided the transfer of technology from advanced global companies. Accordingly, the control system for core technology development and localization is urgently needed. This paper presents modeling and simulation using by PSS/E about generator, governor, exciter, and power system stabilizer for control system in Sihwa tidal power plant to improve the efficiency and develope of core technology. And the dynamic characteristics of governor and exciter were analyzed.

• 전기전자학회논문지
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• 제19권4호
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• pp.603-609
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• 2015

열 쾌적 제어는 실내 환경의 질을 나타내는 기본 요소로써 건물에서 사용되는 에너지와 거주자의 만족도에 매우 밀접하게 연관되어 있다. 본 논문에서는 실내의 쾌적 상태(Predictive Mean Vote)를 검출하고, 목표 소비 전력 내에서 냉난방 온도, 습도, 풍량을 제어함으로써 에너지를 절감하고 근무자에게 쾌적한 환경을 제공할 수 있는 스마트 쾌적 제어 알고리즘을 제안하였다. 시뮬레이션 결과, 열 쾌적 제어에 의한 냉난방제어는 기존의 일반 냉난방기에 비해서 실내의 쾌적도는 그대로 유지한 상태에서 0.5kW의 전력을 절감할 수 있고, 조명제어 알고리즘이 적용된 조명 제어에 의해서 49.2%의 조명 개선 효과가 이루어짐을 알 수 있었다. 시뮬레이션을 통해서 검증된 쾌적 제어 알고리즘을 기존의 냉난방기에 적용할 경우 쾌적도는 유지하고 에너지는 절감할 수 있을 것으로 예상된다.

• 설비공학논문집
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• 제24권6호
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• pp.461-466
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• 2012

Recently, building energy systems with solar collector and solar module have increased to improve energy problem, a heat island, a global warming and carbon dioxide emissions. In this study, value of solar radiation in areas was analyzed using TRNSYS simulation, and the optimum tilt and orientation angle for installing a photovoltaic module was examined. Average values of the weather data in the past twenty years in areas were used as input data. The results show that the tilt angle of a photovoltaic module for gaining the annual maximum solar radiation varies in different localities, and values of the annual solar radiation gained by using the variable photovoltaic module increased by 2.5 percent as compared with that gained by using the fixed photovoltaic module. When fixed photovoltaic module is installed, it should be examined the tilt and orientation angle for installing a photovoltaic module was examined.

• 한국태양에너지학회 논문집
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• 제28권2호
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• pp.50-57
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• 2008

This study intends to evaluate the effect on indoor environment(annual thermal load, sunshine)by the application of the movable horizontal shading device on summer and winter season. For these purpose, we supposed the models which are composed of the several horizontal shading devices. Then we analyzed the simulation using the IES5.5.1 and Seoul weather data. The results of this study are as follows: 1) The proper length, angle of horizontal shading device is 2.1m, 28 degree, respectively. 2) The decreasing rate of the annual load of the Movable Horizontal Shading Model(MHSM) in comparison with the No Shading Model(NSM) & Conventional Horizontal Shading Model(CHSM) is 31.11%, 6.63% respectively. 3) The decrease of sunshine of the MHSM on summer season is effective the alleviation of visual displeasure. On the other hand, the increase of sunshine of the MHSM on winter season is effective the psychological comfort. Further study is to be required the sensitivity analysis on the various shading length for the realistic proper shading length.

• 한국지열·수열에너지학회논문집
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• 제8권4호
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• pp.32-40
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• 2012

Geothermal heat pump(GHP) systems use vertical borehole heat exchangers to transfer heat to and from the surrounding ground via a heat carrier fluid that circulates between the borehole and the heat pump. An Important feature associated with design parameters and system performance is the local thermal resistances between the heat carrier flow channels in the borehole and the surrounding ground. This paper deals with the in-situ experimental determination of the effective thermal properties of the ground. The recorded thermal responses together with the line-source theory are used to determine the thermal conductivity and thermal diffusivity, and the steady-state borehole thermal resistance. In addition, this paper compares the experimental borehole resistance with the results from the different empirical and theoretical relations to evaluate this resistance. Further, the performance simulation of a GHP system with vertical borehole heat exchangers was conducted to analyze the effect of the borehole thermal resistance on the system performance.