• 대한기계학회논문집B
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• 제25권4호
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• pp.554-560
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• 2001

Hydrophilic treatment of the packing materials in a cooling tower has been made by the ion assisted reaction (IAR) method to increase the wettability of the packing materials. The effects of hydrophilic treatment of packing materials on the performance of a cooling tower have been investigated in a wide range of operating parameters, such as water flow rate, air flow rate, and the water inlet temperature. A pilot cooling tower has been designed and built to model a counter-flow cooling tower. The results obtained indicate that the packing characteristic value with hydrophilic packing could be substantially increased by 6∼19.3% than that with conventional packing in the operating ranges considered. The correlations of the packing characteristic value as a function of water-to-air ratio are suggested for a counter-flow cooling tower with hydrophilic packing as well as with conventional packing.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1261-1266
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• 2008

Experimental study was performed to understand the operations of a showcase working in a discount store. Temperatures of evaporation, condenser were measured and also electric power consumption of compressor were measured. The purpose of this study is to application use of cold-heat storage systems operated the showcase. At the condition using ice storage system, the ice making process was operated during midnight being not needed the cooling of the showcase through the continuous running of the condenser unit. And then, the refrigerant was sub-cooled using stored cold-heat after being discharged from the air cooling condenser during the day time. The cooling performance was increased owing to the sub-cooling of refrigerant during day time, hence the running time of the compressor was effectively decreased. In other words, this study showed that power consumption during daytime can be transferred to the midnight for making use of the refrigerant sub-cooling. So the operating characteristics of the showcase system under various working conditions were analyzed and discussed.

• 한국세라믹학회지
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• 제44권4호
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• pp.224-229
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• 2007

To evaluate the cooling rate of clinker quantitatively, several clinkers with different cooling rate were made in the laboratory. The X-ray diffraction pattern of Ferrite 002 reflection were measured and the parameters were calculated by using split type pseudo-Voigt function. The X-ray diffraction patterns of the Ferrite phase in the clinkers from cement manufacturing plant were analyzed by using the parameters and the analysis program was developed to calculate the cooling rate quantitatively. The cooling rate coefficients of the clinkers were calculated by using the profile fitting method of the program and the influence of cooling rate on strength was evaluated. The results show that there is a close relation between the cooling rate of clinker and the strength of cement.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.71-72
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• 2006

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.215-220
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• 2006

Along with socioeconomic development and improving standard of living, the heat demand for heating and cooling in residential and commercial sectors is expected to expand rapidly, reaching over 43 million TOE by 2010 in Korea(about 80% increase compared with that in 1995). Since most of this heat demand is loop temperature below $60^{\circ}C$, the utilization of 'unused energy' is surely one of very effective measures to both environmental preservation and energy conservation. 'Unused energy' in this paper is implicated as 'temperature differential energy' available from treated sewage water, useful and abundant heat source for heat pump(cooler in summer and warmer in winter than outside air). An analysis was carried out to estimate the energy potential of treated sewage water for heat pump heat source. Some analysis were taken to study the characteristics of a heat pump system using the treated sewage water as heat source.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.203-208
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• 2009

This paper presents demonstration study results derived through field testing of a solar assisted cooling and heating system for the library of a cultural center building located in Gwangju, Korea. The area of demanded cooling and heating for building was about 350m2. Solar hot water was delivered by means of a 200m2 array of evacuated tubular solar collector (ETSC) to drive a single-effect (LiBr/H2O) absorption chiller of 10RT nominal cooling capacity. From March in 2008 to February in 2009, demonstration test were performed for solar cooling and heating system. After experiments and analysis, this study found that solar thermal system was 84% for the solar hot water supply and 12% for space heating and 4% for space cooling.

• 동력기계공학회지
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• 제22권6호
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• pp.44-50
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• 2018

As a type of bolt with a spherical head, the ball stud is widely used as a part of a ball joint in steering or suspension systems in automobiles. Balls and studs are subjected to heat treatment suitable for each material; in particular, the shear strength of the ball stud must meet the specifications of the production company. This study evaluated the shear strength of joints according to the cooling method of ball studs subject to resistance welding. The shear stress of water cooling was higher than that of air cooling (as-received material). Note, however, th at oil cooling showed lower stress than that of as-received. When judged by standard deviation, mean, and coefficient of variation according to the arithmetic statistics and shape parameter as well as scale parameter, oil cooling is suitable.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.203-208
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• 2006

The unutilized energy in urban area is commercially and environmentally worth recycling since it can be used as a good energy resource for the heating and cooling supply. Therefore, once heating and cooling demands are near the available unutilized energy resources, a high performance district heating and cooling can be realized by the network of unutilized energy technology. In relation to this circumstance, a road map of the unutilized energy technology is presented in this study.

• Journal of the Optical Society of Korea
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• 제7권2호
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• pp.119-125
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• 2003

We demonstrate parametric resonance in a magneto-optical trap. When we modulate the intensity of the cooling laser at about twice the resonant frequency of the trap, the atoms in the trap are divided into two parts and oscillate with 180 degree phase difference with the finite length due to nonlinearity of the trap potential. These are the effects of general nonlinear dynamics, called the Hopf bifurcation, or limit cycle motion. The amplitude and the phase of the oscillations are measured and compared with the theoretical calculations based on simple Doppler cooling theory. The experimental results are in excellent agreement with the simulation results based on the simple Doppler cooling theory.

• Asian-Australasian Journal of Animal Sciences
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• 제4권2호
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• pp.131-136
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• 1991

Four male swamp buffaloes weighing $460.5{\pm}44.6kg$ were used to study the effects of different cooling techniques on draught capacity. Each animal carted an 882 kg load on the same asphalt road for one hour during four different time periods: 9:00-10:00 A.M., 10:30-11:30 A.M., 2:00-3:00 P.M. and 3:30-4:30 P.M. Simultaneously, all animals were subjected to five different treatments on five days of similar environmental conditions. In Treatment 1, animals were put stationary in a field and did no work; in Treatment 2, animals were worked without any cooling method; in Treatment 3, fifteen-minute wallow was allowed to animals prior to working; in Treatment 4, animals were covered with wetted jute bags while working, and in Treatment 5, two buckets of water were poured over the buffaloes' trunks just prior to working. The experiment was conducted from April to July 1989, when the weather was very hot. It was found that cooling methods and working times did not affect the draught efficiency of buffaloes during the one hour, but did affect physiological traits. The work load had a larger partial effect on physiological responses of buffalo other than respiration rate than did climatic variables except on the respiration rate of the buffaloes. One cooling technique that seemed to slow the increase of body temperature while working was covering the buffalo's back with wetted jute bags. Animals working at different times had significant differences in the increase of physiological traits except pulse rate.