• 한국환경복원기술학회지
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• 제20권5호
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• pp.67-81
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• 2017

Because of lack of accurate understanding of the mechanism of urban heat island (UHI) phenomenon and lack of scientific discussion, it is hard to come up with effective measures to mitigate UHI phenomenon. This study systematically described the UHI and suggested the solutions using green-infrastructure (green-infra). The factors that control UHI are very diverse: radiant heat flux, latent heat flux, storage heat flux, and artificial heat flux, and the air temperature is formed by the combination effect of radiation, conduction and convection. Green-infra strategies can improve thermal environment by reducing radiant heat flux (the albedo effect, the shade effect), increasing latent heat flux (the evapotranspiration effect), and creating a wind path (cooling air flow). As a result of measurement, green-infra could reduce radiant heat flux as $270W/m^2$ due to shadow effect and produce $170W/m^2$ latent heat flux due to evaporation. Finally, green-infra can be applied differently on the macro(urban) scale and micro scale, therefore, we should plan and design green-infra after the target objects of structures are set.

• 설비공학논문집
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• 제11권6호
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• pp.709-715
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• 1999

To optimize a heating and cooling system, we need an exact solution lot radiant heat transfer in any form of room or building. This paper describes the solution method of view factor by the area weighted average and graphical method to calculate the radiant heat exchange or daylighting level in any form of room or building. This study shows that the area weighted average and graphical methods have many points of merits(calculation speed, correctness and calculation capability in an arbitrary form of room shapes etc.) compared with existing methods

• Architectural research
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• 제16권4호
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• pp.203-210
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• 2014

The packaged terminal air conditioner, the typical cooling system for the residential buildings, consumes a large amount of electricity in a short period time during peak hours. In order to reduce the peak load and conserve the electricity, the thermally activated building system can be used as a secondary system to handle the partial cooling load. However, the thermally activated building system may cause condensation and under-cooling. Thus, design of both systems should be performed with careful investigation in characteristics of both systems to amplify the advantages. Since the thermally activated building system has the time-delay effect which may cause under-cooling, the system is designed to handle the base load of the building. Hence, simple simulation with EnergyPlus was performed to observe the characteristics of cooling load in residential buildings. Once the possible range of the load handling ratio of the thermally activated building system was decided, characteristics of system was analyzed in terms of hardware component and operation parameters. The hardware components were analyzed in plant and system aspects and the operation parameter was evaluated in the thermal comfort aspect. As the load handling ratio increased, the thermal comfort increased due to the lower radiant mean temperatures. Within the range of thermal comfort, the several adjustments were made in setpoint temperature and electricity consumptions of difference cases were observed to decide which components and parameters were important for designing the systems.

• 한국가금학회지
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• 제21권3호
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• pp.207-217
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• 1994

This is to provide basic information and technical data, supported by literature search, for use in designing and /or evaluating ventilation systems for broiler shelters. At first, the general design information including weather data, building requirements, ventilation requirements, and supplemental heating and cooling, was presented. Then, environment requirements for broilers, which are for temperature, humidity, air movement, radiant heat, were described and the optimal ventilation systems for broiler were developed.

• 설비공학논문집
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• 제18권4호
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• pp.287-296
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• 2006

In this paper, optimal control strategy of the air-conditioning system with slab thermal storage was investigated based on the optimal control theory. An optimal heat output to the plenum chamber and the air-conditioned room was determined based on two kinds of criterion functions. The first one requires small deviation in room air temperature from a set-point value and low energy consumption. It is shown that the optimized control is to store heat through the whole storage time and to increase storage rate gradually with time. As the second case, a criterion that both a deviation of operative temperature from a set-point temperature and the energy consumption should be minimized was adopted. The room air temperature was a little high and the cooling load during storage time was reduced, compared with the results when a criterion function considering only the room air temperature is used.

• 한국태양에너지학회 논문집
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• 제28권5호
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• pp.14-20
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• 2008

As the number of buildings that use the transparent permeation materials as the outer wall is on the increase, the coming amount of the light rays is a lot, and thus the increase in the cooling load and the radiant heat of high temperature may cause the residents to discomfort. In order to reduce such influences, this paper analyzed the installation effects of the sunshade BIPV. The inner temperature of the room installed the sunshade BIPV or otherwise was measured, and compared and analyzed the effects of reducing the cooling load by the incoming light rays. The sample space of the third floor of S university installed the sunshade BIPV has two rooms on the same conditions, and for five sunny days selected in August, the researcher measured the air temperature and the temperature of the fittings with closing the windows to minimize the movement of air without operating the coolers. The maximum cooling load measured by the incoming light rays in the room where the sunshade BIPV was not installed was examined as 459.13kcal/h. It can be understood as the effect of reducing the cooling load according to the incoming rays of the room with sunshade BIPV. Even though the effect of cooling load reduction is not so great in a room, the total reduction in cooling room for the 32 rooms installed the sunshade BIPV was estimated to be 40442.27kcal/day, which will be able to bring the maximum reduction effect of 17.1kW in energy and reduce the investment cost owing to the reduction in cooling load when initially designing the building.

• 한국태양에너지학회 논문집
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• 제32권5호
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• pp.25-30
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• 2012

Ground source heat pumps(GSHPs) are among the most efficient and comfortable heating and cooling technologies currently available, because they use the earth's natural heat to provide heating, cooling, and often, water heating. And Building Integrated Geothermal System(BIGS) is one of GSHPs which install ground heat exchanger(GHE) in energy pile without borehole to save the investment cost. Therefore, the experiment is to evaluate the heating performance of BIGS in Korea. The experimental results indicate that the average heat pump COP and overall system's COP values are approximately 4.4 and 3.0 in one week. This study shows that the BIGS could be used for heating in Korea.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.285-290
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• 2009

The main thrust of this paper is to investigate acceptable supply air conditions of a dedicated outdoor air system (DOAS) for highrise apartment buildings. As for a typical $132-m^2$ apartment unit, it was assumed that centralized DOAS-Ceiling Radiant Cooling Panel was installed. Transient behavior and control characteristics of each system were modeled numerically using a commercial equation solver program. The optimized dew point temperature of the DOAS was discussed on the basis of the ASHRAE standard 62.1-2007 and the current Korean ventilation standard for apartments. It was found that the optimized dew point temperature of the DOAS supply air accommodating total latent load of a space is $11-12^{\circ}C$ and the appropriate supply air temperature of the DOAS is $11-12^{\circ}C$ in cooling period and neutral temperature of $18-20^{\circ}C$ in intermediate period.

• 한국태양에너지학회 논문집
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• 제32권2호
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• pp.58-63
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• 2012

As the exterior of building has been considered one of th important parts, the use of glass that is suitable to express various appearances gets raised. However, windows have 6~7times lower insulating performance than insulated walls. Lately, highly efficient windows are required as the needs for reduction of energy consumption come to the force. Therefore, Nowadays more people use cooling systems in summer, more the use of Low-E glazing is increasing. Because it is good to block Solar Radiant Energy which can cause much of heat loss while cooling system is working. This study measures U-value of the double Low-E glazing window and commonly used single Low-E glazing window. And then the effect of each window on the efficiency rating has been analyzed applying to the certification system of the building energy efficiency rating which has implemented.

• 설비공학논문집
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• 제28권10호
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• pp.387-393
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• 2016

A ground source heat pump system maintains a constant efficiency due to its stable heat source and radiant heat temperature which provide a more effective thermal performance than that of the air source heat pump system. As an eco-friendly renewable energy source, it can reduce electric power and carbon dioxide. In this study, we analyzed one year of data from a web based remote monitoring system to estimate the thermal performance of GSHP with the capacity of 3RT, which is installed in a low energy house located in Daejeon, Korea. This GSHP system is a hybrid system connected to a solar hot water system. Cold and hot water stored in a buffer tank is supplied to six ceiling cassette type fan coil units and a floor panel heating system installed in each room. The results are as follows. First, the GSHP system was operated for ten minutes intermittently in summer in order to decrease the heat load caused by super-insulation. Second, the energy consumption in winter where the system was operated throughout the entire day was 7.5 times higher than that in summer. Moreover, the annual COP of the heating and cooling system was 4.1 in summer and 4.2 in winter, showing little difference. Third, the outlet temperature of the ground heat exchanger in winter decreased from $13^{\circ}C$ in November to $9^{\circ}C$ in February, while that in summer increased from $14^{\circ}C$ to $17^{\circ}C$ showing that the temperature change in winter is greater than that in summer.