• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.90-95
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• 2008

An SHGC(Solar Heat Gain Coefficient) is a determinant of total flux of solar radiation coming indoor and a critical factor in evaluating heating and cooling load. U-value represents heat loss while SHGC denominates heat gain. Recently, windows with high solar gain, mid solar gain or low solar gain are being produced with the development of Low-E coating technology. This study evaluated changes in energy consumption for heating and cooling according to changes in SHGC when using double-layered Low-E glass and triple layered Low-E glass in relation to double layered clear glass as base glass. An Office was chosen for the evaluation. For deriving optical properties of each window, WINDOW 5 by LBNL, an U.S. based company. and the results were analyzed to evaluate performance of heat and cooling energy on anannual basis using ESP-r, an energy interpretation program. Compared to the energy consumption of the double layered clear glass, the double layered Low-E glass with high solar gain consumed $69.5kWh/m^2,yr$, 9% more than the double layered clear glass in cooling energy. The one with mid solar gain consumed $63.1kWh/m^2,yr$, 1% less than the base glass while the one with low solar gain consumed $57.6kWh/m^2,yr$, 10% less than the base glass. When it comes to tripled layered glass, the ones with high solar showed 2% of increase respectively while the one with mid solar gain and low solar gain resulted 5% and 11% in decrease in energy consumption due to low acquisition of solar radiation. With respect to cooling energy. it was found that the lower the SHGC. the less energy consumption becomes.

• Elastomers and Composites
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• v.59 no.1
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• pp.22-33
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• 2024

Passive radiative cooling is a promising technology for cooling objects without energy input. Passive radiative cooling works by radiating heat from the surface, which then passes through the atmosphere and into space. Achieving efficient passive radiative cooling is mainly accomplished by using materials with high emissivity in the atmospheric window (8-13 ㎛). Research has shown that polymers tend to exhibit high emissivity in this spectral range. In addition to elastomers, other materials with potential for passive radiative cooling include metal oxides, carbon-based materials, and polymers. The structure of a passive radiative cooling device can affect its cooling performance. For example, a device with a large surface area will have a greater amount of surface area exposed to the sky, which increases the amount of thermal radiation emitted. Passive radiative cooling has a wide range of potential applications, including building cooling, electronics cooling, healthcare, and transportation. Current research has focused on improving the efficiency of passive radiative cooling materials and devices. With further development, passive radiative cooling can significantly affect a wide range of sectors.

• KIEAE Journal
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• v.16 no.2
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• pp.5-10
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• 2016

Purpose: Recently, many public office buildings which were built by curtain wall increased rapidly, but the results of the investigation of the government, these buildings have been found that the heating and cooling thermal load is high, and showed low energy efficiency. Method: To evaluate the effects by applying outdoor louver and indoor blind, which can control solar radiation in order to reduce the heating and cooling load of public office building which was built by glass curtain wall. The heating and cooling load was calculated via Energyplus, building and outdoor louver, indoor blind were modeled by Google sketchup connected to Energyplus. Result: The results of this study were as follows; the case of applying various outdoor louver, the heating and cooling load all decreased as compared to the case without applying outdoor louver, the case of applying indoor blind, the heating and cooling load decreased as compared to the case without applying indoor blind, but indoor blind showed low energy performance comparing outdoor louver.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.4
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• pp.137-144
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• 2016

Commercial buildings account for a significant proportion of the total building energy use in Korea, and cooling energy, in turn, accounts for the largest proportion of total energy consumption in commercial buildings. Under this circumstance, chiller staging is considered to be a reasonable and practical solution for cooling energy saving. In this study, the part-load ratio and the operating characteristics of a vapor compression chiller were analysed within an office building. In addition, energy consumption among different chiller staging schemes was comparatively analysed. As a result, significant proportions of total operating hours, cooling load and energy consumption turned out to be in the part load ratio range from 0% through 50%, and thus energy consumption was significantly affected by the chiller COP at low part-load conditions, indicating that the chiller operation at the part-load is an important factor in commercial buildings. In addition, utilizing a sequential chiller staging scheme can reduce the annual cooling energy usage by more than 10.3% compared to operating a single chiller.

• Journal of computational fluids engineering
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• v.21 no.2
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• pp.106-111
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• 2016

Waste-to-energy facilities including incinerators are known as an efficient method to reduce wastes. In waste-to-energy facilities, more efficient cooling system is still needed for grates as the energy density of waste increased. For better cooling performance with the water-cooled grates, optimal design of cooling water pathways is highly beneficial. We performed numerical investigation on fluid flow and residence time of cooling water with change of the geometry of the cooling water pathway. With addition of round shaped guide vanes in the water pathway, the maximum residence time of flow is reduced(from 4.3 sec. to 2.4 sec.), but there is no significant difference in pressure drop between inlet and outlet, and average residence time at the outlet. Furthermore the flow stagnation region moves to the outlet, as the position of the round shaped guide vanes is located to the neck point of pathways.

• Journal of Power System Engineering
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• v.18 no.3
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• pp.73-78
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• 2014

Recently, Free cooling system usage has increased at many buildings in intermediate and winter season. Free cooling system is used to reduce the energy consumption of refrigeration in that season. Free cooling system is refrigeration system using cooled water. In general, this system is applied with the building having refrigeration load at all time such as a data center. In this study, energy consumption of a data center taking free cooling system in Ulsan was evaluated by the software HYSYS. the main result is as in the following : free cooling system is effective from January to April and from November to December. In case of Ulsna in 2013, using free coolng system is able to spend refrigeration energy of about 15% less than existing system. According to this result, it is appropriated that free cooling system is used in building having refrigeration load at all time such as data center.

• Journal of the Korean Solar Energy Society
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• v.26 no.3
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• pp.119-125
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• 2006

The impacts of climate changes on building energy demand were investigated by means of the degree-days method. Future trends for the 21st century was assessed based on climate change scenarios with 7 global climate models(GCMs). We constructed hourly weather data from monthly temperatures by Trnsys 16. A procedure to estimate heating degree-days (HDD) and cooling degree-days (CDD) from monthly temperature data was developed and applied to three scenarios for Inchon. In the period 1995-2080, HDD would fall by up to 70%. A significant increase in cooling energy demand was found to occur between 1995-2004(70% based on CDD). During 1995-2080, CDD would Increase by up to 120%. Our analysis shows widely varying shifts in future energy demand depending on season. Heating costs in winter will significantly decrease whereas more expensive electrical cooling energy will be needed.

• Journal of the Korean Solar Energy Society
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• v.25 no.4
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• pp.53-60
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• 2005

The purpose of this study is to improve energy efficiency of windows in office buildings through the evaluation of their heating, cooling and illumination load. Energy efficiency is influenced by window size which is determined at the early stage of building design. The process of this study is as follows. First, energy performance is analysed according to the various rates of windows through computer simulation (ECOTECT). Then, the annual heating, cooling and illuminating loads according to the different window sizes are compared one another. Results indicated that the optimal window size considering energy efficiency is 50% of the surface area. When the window size is 50% of the surface area, annual maintenance expense is also smallest. Since the cost of cooling is larger than that of heating, too low indoor air temperature in summer is unfavorable based on the reasonable annual maintenance expenses.

• Journal of the Korean Solar Energy Society
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• v.31 no.4
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• pp.34-40
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• 2011

Apartment Housing has been increasing steadily, particularly our current super high-rise apartment houses that represent the culture has become a trend in Korea. These super high-rise apartment houses' curtain wall system increases heating and cooling loads, it is expected to vary by each unit's thermal properties. In this study, measured indoor environment and energy simulation results were compared to actual energy consumption. As a result, the various factors that affect heating and cooling loads, such as direction, plan type and glazing area, influence each unit's load characteristic. In particular, according to the electricity costs savings behavior, the occupant's thermal discomfort is expected to be large in summer. Therefore, to reduce heating and cooling load for each unit requires a reasonable plan.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.16 no.4
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• pp.1-8
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• 2020

For a central cooling system of a medical facility composed of absorption chiller and screw chiller, the study was conducted on how to minimize the energy cost. In consideration of the energy cost, the optimal operation method in which the operation method of the heat source is changed according to the size of the cooling load was derived through simulation analysis. When applying the optimal operation method, the indoor environment, energy consumption, and energy cost were analyzed and compared with the reference operation method.