• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.93-100
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• 2002

This study was carried out not only to develop CFD model for numerically simulating fog cooling system but also to verify the validity of the developed model by data measured in fag cooling greenhouse. In addition the developed model was applied to investigate the effects of spraying water temperature, spraying water amount, spraying interval and evaporation percentage on the performance of the fog cooling system. According to the simulation results, the temperature differences between the measured and predicted temperatures at each measurement point were $0.1~1.4^{\circ}C$ in case of no shading and $0.2~2.3^{\circ}C$ in close of shading. The humidity differences were 0.3~6.0% and 0.7~10.6%, respectively in the cases of no shading and shading. Because the predicted data showed a good agreement with the measured ones, the developed model is supposed to be able to predict the cooling effect of the fog cooling system. The performance of fog cooling system was greatly influenced by spraying water amount, spraying interval and evaporation percentage, but it was not influenced by spraying water temperature.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.6
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• pp.534-539
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• 2009

One of the most efficient techniques improving the heat transfer performance of a diesel electric generation is a corrosion control in jacket cooling water system. The environmental parameters most affecting corrosion are dissolved salt concentration, temperature, and pH of cooling water. No corrosion occurs in carbon steel probe at pH 11 in normal operating condition of diesel electric generation cooling water. pH control agent in this study is trisodium phosphate. pH control appears to be the most convenient way to enhance the thermal performance of a diesel electric generation.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1146_1147
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• 2009

This experiment is significant because we can provide information by measuring effect of energy saving for whom plan to install a geothermal heat & cooling system. The result shows geothemal system can save about 50% of energy(heating : 35%, cooling : 60%) and we verified that when using curtain can help saving 4~12% of energy additionally.

• Journal of the Korean Institute of Educational Facilities
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• v.18 no.3
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• pp.35-41
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• 2011

Performance of a small-capacity solar absorption cooling system was investigated experimentally. Ten sets of evacuative-tube solar-heat collectors and a 5 kW single-stage absorption cooler were combined to produce a hybrid cooling system. The performance of the cooling system was measured using a tim-coil unit installed in a small plastic storage. It was found from the test on a sunny day of May that when the temperature of the hot water supplied from the solar collectors to the generator of the absorption cooler reached $60^{\circ}C$, the absorption cooler started cooling and the cold water temperature measured from the fan-coil unit reached $18^{\circ}C$. The COP, which is defined as the ratio of the cooling power to the total electrical power input was higher than 1.0.

• Journal of Energy Engineering
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• v.20 no.4
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• pp.259-266
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• 2011

Following the reactor shutdown, the reactor shutdown cooling system must be designed to supply the coolant sufficiently not only to remove the decay heat but to maintain the adequate cooling rate to protect the reactor equipments. In this study, KDESCENT code for the light water reactor and SOPHT, SDCS codes for the heavy water reactor were compared and analyzed to investigate the cooling capability during the shutdown cooling process. The shutdown cooling system design requirements were satisfied during cooling process for both the SDCP and the HTP modes and the design cooling rate of $2.8^{\circ}C/min$ or below was maintained using the SDC heat exchangers. This study shows that the shutdown cooling system in the Wolsong 2, 3, 4 reactors provides sufficient cooling to maintain the nuclear fuel integrity by removing the decay heat of the nuclear fission product.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.113-117
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• 2006

This paper Is for development of cooling module in order to maintain heat and water balance in fuel cell vehicle. Thermal management system for fuel cell is disadvantage because the temperature of coolant is lower than that of ICE and heat duty of radiator is higher. By CFD simulation, cool ing module was developed for water balance of system. Hot chamber test and hot area/high altitude test on cool ing module was completed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.3
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• pp.251-257
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• 2000

District heating and cooling systems offer highly efficient energy utilization and maintenance by centralizing heat management. More pumping power, however, is required because the water has to travel long distance from heat source to the users. In the present study, a trace of drag reduction additives is added to the District Cooling system to achieve a significant drag reduction and save pumping power. Water-soluble polymers, surfactants, and environment-friendly degradable polymers are used as effective drag reducing additives. Time dependent percent drag reductions are compared for various additive solutions at 100 wppm concentration for different water velocity. Without as an anionic surfactant, copolymer was most effective in percent drag reduction. It is found that there exists an optimal condition when copolymer is mixed with SDS. An environment-friendly degradable polymer, xanthan gum, is found to be a significant drag reduction additive. Ice slurry systems, can give less pressure drops compared with chilled water system for certain condtions. Drag reduction additives were also effective for the ice slurry system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.1
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• pp.35-40
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• 2006

Heat-pump system has a special feature that provides heating operation in winter season and cooling operation in summer season with a single system. It also has a merit that absorbs and makes use of wastewater heat, terrestrial heat, and heat energy from the air. Because heat-pump system uses midnight electric power, it decreases power peak load and is very economical as a result. By using the property that energy source is converted to low temperature when losing the heat, high temperature energy source is used to provide heating water and low temperature energy source is used to provide cooling water simultaneously in summer season. This study made up a heat-pump system with 4 air heat sources and a water heat source and implemented the optimal operation algorithm that works with numbers of heat pumps to operate them efficiently. With the heat-pump system, we applied it to cooling and heating operation in summer season operation mode in a real building.

• New & Renewable Energy
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• v.3 no.4
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• pp.47-53
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• 2007

Effluent ground water overflow in deep and broad ground space building. Temperature of effluent ground water is in $12{\sim}20^{\circ}C$ annually and the quality of that water is as good as living water. Therefore if the flow rate of effluent ground water is sufficient as source of heat pump, that is good heat source and heat sink of heat pump. Effluent ground water contain the thermal energy of surrounding ground. So this is a new application of ground source heat pump. In this study open type and close type heat pump system using effluent ground water was installed and tested for a church building with large and deep ground space. The effluent flow rate of this building is $800{\sim}1000ton/day$. The heat pump capacity is 5RT each. The heat pump cooling COP is $4.9{\sim}5.2$ for the open type and $4.9{\sim}5.7$ for close type system. The system cooling COP is $3.2{\sim}4.5$ for open type and $3.8{\sim}4.2$ for close type system. This performance is up to that of BHE type ground source heat pump.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.471-476
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• 2007

Effluent ground water overflow in deep and broad ground space building. Temperature of effluent ground water is in $12{\sim}20^{\circ}C$ annually and the quality of that water is as good as living water. Therefore if the flow rate of effluent ground water is sufficient as source of heat pump, that is good heat source and heat sink of heat pump. Effuent ground water contain the thermal energy of surrounding ground. So this is a new application of ground source heat pump. In this study open type and c lose type heat pump system using effluent ground water was installed and tested for it church building with large and deep ground space. The effluent flow rate of this building is $800{\sim}1000$ ton/day. The heat pump capacity is 5RT each. The heat pump cooling COP is $4.9{\sim}5.2$ for the open type and $4.9{\sim}5.7$ for close type system. The system cooling COP is $3.2{\sim}4.5$ for open type and $3.8{\sim}4.2$for close type system. This performance is up to that of BHE type ground source heat pump.