• Structural Engineering and Mechanics
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• v.54 no.5
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• pp.891-908
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• 2015

For a systematic study on wind-induced vibration characteristics of large hyperbolic cooling towers with different feature sizes, the pressure measurement tests are finished on the rigid body models of three representative cooling towers with the height of 155 m, 177 m and 215 m respectively. Combining the refined frequency-domain algorithm of wind-induced responses, the wind-induced average response, resonant response, background response, coupling response and wind vibration coefficients of large cooling towers with different feature sizes are obtained. Based on the calculating results, the parametric analysis on wind-induced vibration of cooling towers is carried out, e.g. the feature sizes, damping ratio and the interference effect of surrounding buildings. The discussion shows that the increase of feature sizes makes wind-induced average response and fluctuating response larger correspondingly, and the proportion of resonant response also gradually increased, but it has little effect on the wind vibration coefficient. The increase of damping ratio makes resonant response and the wind vibration coefficient decreases obviously, which brings about no effect on average response and background response. The interference effect of surrounding buildings makes the fluctuating response and wind vibration coefficient increased significantly, furthermore, the increase ranges of resonant response is greater than background response.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.46-51
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• 2006

In order to utilize the refrigerants condensation heat of condenser on the absorption chiller system, the solution cooling condenser(SCC) were proposed, which weak solution of absorber outlet use as a cooling water. As the UA of the solution cooling condenser increased, increasement of COP is about maximum 0.09 in occasion of single effect and is about maximum 0.08 in occasion of double effect series flow. In the case of heat exchanger efficiency is about 0.85, it's increments are 0.08 and 0.072, each. And solution cooling condenser is a more effective device in the single effect absorption system more than double effect system for the principle of operation. In order to increases the heat of solution cooling condenser, if reduce the flow rate of cooling water or the value of UA, it makes COP increase a little, but it brought COP decrease because of increasing the pressure of system.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.18 no.4
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• pp.33-44
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• 2022

In this study, we analyze the existing heating and cooling operation method for an office-type complex building with a central heating and cooling system, and examine the effects of applying various EMS that can be applied according to the load size to save energy in the building. For this purpose, simulation analysis was performed. As a control method, reset control of chilled water, hot water, cooling water and supply air temperatures, optimal start/stop of heat source, and number of heat source control were applied according to the load size, and energy consumption was analyzed accordingly. In addition, when all of these control methods were applied, the overlapping energy saving effect was finally confirmed. As a result, it was possible to confirm the energy saving effect when EMS for reset control and heat source control were applied compared to the existing control method of the heating and cooling system, and the effect for the case of using all these control methods in combination was also confirmed.

• Journal of Power System Engineering
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• v.12 no.4
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• pp.32-38
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• 2008

The improvement of cooling ability for the air conditioner is the most efficient method of application of its system. Therefore, this study has been investigated the improvement of cooling ability for the air conditioner using automotive by attached of a thermoelectric module. According to the result of test, capacity of the thermoelectric module make temperature range from $-75^{\circ}C$ to $+300^{\circ}C$ possible to cooling and exothermic. In addtion to, the reduction effect of energy revealed and the effect of liquid hammer remained with safety by attached the thermoelectric module. It was found that the air conditioner system by attached thermoelectric module have better cooling ability than the air conditioner system of existing vehicle.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.4
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• pp.249-253
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• 2000

Data obtained from a cruise from 4~12 December, 1998 was analyzed to estimate the mixing effects of wind, surface cooling, and tide. A band denoting a mixing area with a temperature difference of less than 1$^{\circ}C$ between the sea surface and the bottom extended 40~60 km from the coast into the open sea, following 125$^{\circ}$ 30\` E in longitude. This band was divided into two areas; a well-mixed area close to the coast and a stratified region in the open sea. The mixing effect due to the wind was only 2%, yet the mixing effect due to the tides was about 68%. This indicates that surface cooling and tides were the major factors involved in the mixing mechanism on the west coast during the cooling season.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.6
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• pp.5-11
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• 1994

We have investigated the variation of dwell and warm-up time for effects of positioning accuracy of the CNC machine tools with an laser measuring system. Also, we strdied the effect of improvement of the positioning accuracy by variation of the temperature for hollow ball screw, which mostly used as drive mechanism of CNC machine tools. We dbtained the effectiveness of cooling effect of the new cooling system, compared with the conventional cooling system.

• Journal of Power System Engineering
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• v.10 no.4
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• pp.11-16
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• 2006

This research is to verify the cooling effect of the acting surface on the rotary motor using heat pipe and conventional cooling fan. In order to show the cooling performance of the rotary motor and heat pipe with the fin-typed heat sink, the surface temperature of the motor and condenser was measured in real time. The experiments were also conducted as for not only cooling device installed with heat pipe only, but with heat pipe and conventional cooling fan simultaneously. The present experiment reveals that the cooling combination of the heat pipe and cooling fan is far superior to the conventional cooling device for the driving motor such as the fin-typed heat sink. When the driving voltage of 20V and 14V were supplied to the driving motor, the cooling performance of the rotary motor with heat pipe was 170% and 500%, respectively better than that without heat pipe on steady state condition.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.10
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• pp.60-67
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• 2006

This paper presents the temperature control in aluminum plate with Peltier module. From the experimental work, Peltier module is used to control the temperature of small aluminum plate for both heating and cooling with the control of current and fan ON/OFF. And current control of Peltier module was accomplished by PWM method. As a result of experiments, it is proper that operate cooling fan only while cooling duration and there exist a proper cooling current to drop temperature rapidly. It takes about 125sec to control temperature of aluminium plate between $30^{\circ}C$ and $70^{\circ}C$ and about 70sec between $40^{\circ}C$ and $60^{\circ}C$, in ambient temperature $28^{\circ}C{\sim}29^{\circ}C$ while cooling fan is operated only cooling duration. With the cooling current, temperature control of aluminum plate was accomplished more rapidly in comparison without cooling current. Future aim is to realize more rapid temperature control and develop SMHA(special metal hydride actuator) by using Peltier module as a heating and cooling source.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.7-12
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• 2016

This paper deals with a parametric study on cooling channel configurations to enhance the cooling effect. As a cooling effect has been increased, the exhaust gas by the plant from a manufacture is becoming deceased. To solve this problem, the design of a efficient cooling system is needed. In this paper, the cooling channel was analyzed to improve the cooling performance. The heat transfer rates depending on the number of baffle and the heiht of fin were obtained by using numerical simulation method. Three-dimensional Reynolds-averaged Naiver-Stokes equations were used to estimate flow and heat transfer in cooling channel, and the $k-{\varepsilon}$ model for turbulence closure was employed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1131-1139
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• 2001

Experimental results are presented, which describe the effect of blowing ratio on film cooling from two rows of holes with opposite orientation angles. The inclination angle is fixed at 35°, and the orientation angles are set to be 45°for the downstream row, and -45°for the upstream row. The studied blowing ratios are 0.5, 1.0 and 2.0. The boundary layer temperature distributions are measured using thermocouple at two downstream locations. Detailed adiabatic film cooling effectiveness and heat transfer coefficient distributions are measured with TLC(Thermochromic Liquid Crystal). The adiabatic film cooling effectiveness and heat transfer coefficient distributions are discussed in connection with the injectant behaviors inferred from the boundary layer temperature distributions. Film cooling performance, represented by heat flux is evaluated from the adiabatic film cooling effectiveness and heat transfer coefficient data. The results show that the investigated geometry provides improved film cooling performance at the high blowing ratios of 1.0 and 2.0.