• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.1
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• pp.199-204
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• 2020

In case of the silicon solar panel being used in Korea, the production specification is designed to give maximum output at the limit of -0.5 to 0.05℃, so the output of 0.45~0.55% decreases when the temperature rises by 1℃. As a result, the photovoltaic power generation is reduced according to the surface temperature rise of the photovoltaic module due to the characteristics of the solar cell. The decrease in output reduces the efficiency of photovoltaic power generation, and if the efficiency decreases, the result is that the profit of electricity sales according to the amount of photovoltaic power generation decreases. Therefore, this paper proposes a method of spraying cooling air to the lower (or surrounding) of the photovoltaic module when it is identified above the set temperature by the temperature detection sensor. In addition, the amount of power generated is increased by utilizing the lost solar energy, and by applying cooling function through cooling air, the power generation can be further increased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.4
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• pp.159-166
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• 2018

The Korean fenestration energy consumption efficiency rating system only considers thermal performance of the heat transfer coefficient (U-value) and airtightness excluding optical characteristics of the solar heat gain coefficient (SHGC). This study analyzed annual heating and cooling energy requirements on the middle floor of apartment by optical and thermal performance of windows to evaluate the suitability of the rating system. One hundred and twenty-eight windows were analyzed using THERM and WINDOW 7.4, and energy simulation for a reference model of an apartment house facing south was performed using TRNSYS 17. The results showed that window performance was the main factor in the heating and cooling load. The heating load of the reference model was 539 kWh to 2,022 kW, and the cooling load was 376 kWh to 1,443 kWh. The coefficient of determination ($R^2$) of the heating and cooling loads driven from the SHGC were 0.7437 and 0.9869, which are more compatible than those from the U-value, 0.0558 and 0.4781. Therefore, it is not reasonable to evaluate the energy performance of windows using only the U-value, and the Korean fenestration energy consumption efficiency rating system requires a new evaluation standard, including SHGC.

• Journal of the Korean Solar Energy Society
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• v.31 no.6
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• pp.95-102
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• 2011

The purpose of study is to estimate heating, cooling load performance and economic efficiency in office building with applied the functional paint. this paint can reduced SHGC(Solar Heat Gain Coefficient) on the glazing surface by coating. In this study, estimated to compared with double glazing, low-e glazing, IP(Insulation Paint) and IPu(Insulation UV-Cut Paint) coating glazing. As a result of this study, 1)heating & cooling load Analysis, SHGC value and U-factor of double glazing is about 0.70 and 3.29($W/m^2K$). low-E glazing is about 0.65 and 2.70($W/m^2K$). Two-side it is about 0.27 and 3.25($W/m^2K$). When compared to double glazing, annual heating & cooling load of low-E glazing, Two-side IPu and IP paint coating glazing is 3,012MWh($124kWh/m^2$), 2,910MWh($120kWh/m^2$), 2,867MWh($118.4kWh/m^2$) and 2,867MWh($118.4kWh/m^2$). It i sreduced to 2.0%, 5.2%, 6.7%, and 6.7% respectively. 2)the estimation of economic efficiency, low-e glazing installed in office building can not recover the investment within a lifetime 40years. but IPu and IP paint, two-side coating in glazing, have a payback period of 13 years respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.169-174
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• 2006

This paper is related to a design of high pressure sub-scale combustor with regenerative reeling. As a previous step for the evaluation of thermal heat flux, a similar combustor with cooling water was manufactured. Design conditions with high combustion efficiency and cooling performance were verified through the hot firing tests of the water-cooled high pressure combustor. Finally the regeneratively cooled high pressure combustor has been designed based on these data. After manufacturing it, its practical utility will be tested and verified through hot firing tests.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.30-36
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• 2016

The battery pack which is a main component of E-scooter needs the cooling system because it is the matter of battery safety in spite of the incresing of charge efficiency due to decress the internal resistence in the condition of high temperature. The purpose of this study is to analyse the effects of cooling methods which is the control of air's inlet and outlet operating timing. When each battery had large temperature deviation in the battery pack, the difference of battery's performance and efficiency were appeared. In this study, the cooling performance of battery pack has been improved by changing the operation timing of inlet and outlet fan, it improved the performance and efficiency of battery. The numerical analysis using a commercial code ANSYS CFX version 17.0 were used for the study.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1183-1184
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• 2013

• Journal of Bio-Environment Control
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• v.7 no.3
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• pp.237-245
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• 1998

Greenhouse crop production under critical summer climate In Korea has considerable difficulties because of high temperature and relative humidity. In this study, some water pipes were tested as a means of the dehumidification and increment of evaporative cooling efficiency. As a result of heat transfer characteristic analysis, overall heat transfer coefficient of copper pipe was larger than steel pipe, and estimated values were smaller than measured values. The condensed quantities of vapor were not significantly different between copper pipe and steel pipe, however dehumidifying effect by the water pipes was significantly large. It was estimated based on the results that the evaporative cooling system by the water pipe will be able to increase the evaporative cooling efficiency of about 48%, and decrease the temperature of about 1.3$^{\circ}C$.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.147-152
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• 2015

In order to develop the cooling load estimation method in the greenhouse, the cooling load calculation formula based on the heat balance method was constructed and verified by the actual cooling load measured in the fog cooling greenhouse. To examine the ventilation heat transfer in the cooling load calculation formula, we measured ventilation rates in the experimental greenhouse which a cooling system was not operated. The ventilation heat transfer by a heat balance method showed a relatively good agreement. Evaporation efficiencies of the two-fluid fogging system were a range of 0.3 to 0.94, average 0.67, and it showed that they increased as the ventilation rate increased. We measured thermal environments in a fog cooling greenhouse, and calculated cooling load by heat balance equation. Also we calculated evaporative cooling energy by measuring the sprayed amount in the fogging system. And by comparing those two results, we could verify that the calculated and the measured cooling load showed a relatively similar trend. When the cooling load was low, the measured value was slightly larger than calculated, when the cooling load was high, it has been found to be smaller than calculated. In designing the greenhouse cooling system, the capacity of cooling equipment is determined by the maximum cooling load. We have to consider the safety factor when installed capacity is estimated, so a cooling load calculation method presented in this study could be applied to the greenhouse environmental design.

• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.81-87
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• 2002

This study was conducted to investigate the cooling efficiency and growth of tomatoes by root zone cooling device using a pad-box and cultivated system. The structure of the root zone cooling system using a pad-box was four piece of pads bonded an the side and a fan set at the bottom. Cool wind was generated by the outside air which was punched at intervals of 10 cm along three rows. Cold wind flowed to the root zone in the culture medium. The root zone cooling efficiency of cold wind generation by using a pad-box flowing through a wet-pad was determined. Major characteristic of this cuttural system consist of bed filled with a perlite medium and a ventilation pipe using PVC. The cold wind generation by a pad box (CWP) was compared to that of cold wind generation by a radiator (CWR), cold water circulation using a XL-pipe (CWX) and the control (non-cooling). When the temperature of water supplied was 16.2-18.4$^{\circ}C$, temperatures in the medium were 20.5~23.2$^{\circ}C$ for CWP 22.7~24.2$^{\circ}C$ for CWR, 22.8~24.27$^{\circ}C$ for CWX and 23.1~-29.6$^{\circ}C$ for the control. The results show that the cold wind temperature using the pad-box was lower by 1~2$^{\circ}C$ than that of cold water circulation in the XL-pipe and lower by 5~6$^{\circ}C$ than that of the control. Growth such as leaf length, leaf width, fresh weight and dry weight, was greater in three root zone cooling methods than in the control. Root activity was higher in the rat zone cooling methods than in the control. However, there was no significant difference among root zone cooling methods.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.5
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• pp.413-421
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• 2014

Desiccant cooling system is an air conditioning system that uses evaporative cooler to cool air and it can perform cooling by using heat energy only without electrically charged cooler. Thus, it can solve many problems of present cooling system including the destruction of ozone layer due to the use of CFC[chloro fluoro carbon] affiliated refrigerants and increase of peak power during summer season. In this study, cooling performance and exergy analysis was conducted in order to increase efficiency of desiccant cooling system. Especially, using exergy analysis based on the second law of thermodynamics can resolve the issue related to system efficiency in a more fundamental way by analyzing the cause of exergy destruction both in whole system and each component. The purpose of this study is to evaluate COP[coefficient of performance], cooling capacity and exergy performance of desiccant cooling system incorporating a regenerative evaporative cooler in various regeneration temperature and outdoor air conditions.