• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.6
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• pp.771-778
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• 2002

Cooling clothes especially cooling vest are being considered for as an efficient way to reduce heat strain under hot environment. But wearing ice gel or ice-based cooling vest caused discomfort to subjects due to the weight of vest. Therefore, this study was executed to find efficient cooling parts and to reduce vest weight by cooling only these parts. Two male subjects were exposed to heat(40$^{\circ}C$, 30%RH) with A type(breast+back+abdomen+waist), B type(breast+back+waist), C type(breast+back+abdomen) and D type(breast+back) cooling vest that distinguished with cooling part. The results were as follows; When subjects were C type and D type vest, sweat volume was less and skin temperature was low. Heart rate and rectal temperature were low in B type and D type. These results suggest that excessive cooling of breast and abdomen may exert a bad influence to health and cooling of back is desirable.

• Journal of Power System Engineering
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• v.10 no.4
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• pp.65-70
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• 2006

This study is to experimentally evaluate the cooling performance of the Bonding type and Injection type of heat sink using three different kinds of industrial Peltier module by digital LabViewTM measurement. Injection type of heat sink could be more efficient for the heat transfer than Bonding type, even with 30% more radiating surface area. In addition, the experimental results revealed that the sufficient power supplied was able to show the better cooling performance of Peltier module. In order to verify the optimal cooling performance of the cooling device, two Peltier module, HMN 6040 and HMN 1550 with Bonding and Injection type of heat sink were used. The cooling performance with injection type of heat sink was 2.11% and 6.24% better than that with bonding type of heat sink under the HMN 6040 and HMN 1550, respectively.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.1096-1101
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• 2005

In this study, the experiment of thermal performance about closed-type hybrid cooling tower was conducted. A closed type cooling tower is a device similar to a general cooling tower, but with cooling tower replaced by a heat exchanger. The test section for this experiment has the process that the cooling water flows from top part of heat exchanger to bottom side in the inner side of tube, and spray water flows gravitational direction in the outer side of it. Air contacts of tube outer side are counterflow. The heat transfer pipe used in this experiment is a bare type tube having an outside diameter of 15.88mm. In this experiment, heat performances of the cooling tower are calculated such as overall heat transfer coefficient of between the process fluid and air, cooing capacity and pressure drop.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.359-364
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• 2005

In dehumidification evaporation cooling system. the regeneratie evaporative cooler(REC) makes an important role to reduce the sensible cooling load in the system through evaporative cooling, By this reason, many studies about increasing the cooling capacity of the REC were undertook. In this paper, we analyzed the cooling characteristics of the REC due to the structures of the REC and determined the best structure for the REC's effectiveness and cooling capacity. From the study. we could obtain some important results: at first. corrugated type has the benefit to expand the channel width of the REC, But because the type has some weak points about the size and weight. there is almost no benefit to improve the performance of the REC. Through these reasons. we decided that finned type is the best structure to improve the performance of the REC.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.827-834
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• 2009

The cooling heat transfer coefficient of $CO_2$ in a brazing type small diameter tube was investigated experimentally. The main components of the refrigerant loop are a receiver, a $CO_2$ compressor, a mass flow meter, an evaporator and a brazing type small diameter tube as a test section. The mass flux of $CO_2$ is $400{\sim}1600$ [kg/$m^2s$], the mass flowrate of coolant were varied from 0.15 to 0.3 [kg/s], and the cooling pressure of gas cooler were from 8 to 10 [MPa]. The cooling heat transfer coefficients of the brazing type small diameter copper tube is about $4{\sim}11.7%$ higher than that of the conventional type small diameter copper tube. In comparison with test results and existing correlations, correlations failed to predict the cooling heat transfer coefficient of $CO_2$ in a brazing type small diameter copper tube. therefore, it is necessary to develope reliable and accurate predictions determining the cooling heat transfer coefficient of $CO_2$ in a brazing type small diameter copper tube.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.10
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• pp.394-401
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• 2016

The configuration of an extruded-type cooling structure was optimized for the light-emitting diode (LED) streetlights that have recently replaced convectional metal halide streetlights for energy saving. Natural convection and radiative heat transfer over the cooling structure were simulated using a numerical model with experimental verification. An improved cooling structure type was suggested to overcome the previous performance degeneration, as confirmed by analyzing the thermal flow around the existing cooling structure. A parameter study of the cooling structure geometries was also conducted and, based on the numerical results, the configuration was optimized to reduce the weight of the cooling structure. Consequently, the mass of the cooling structure was reduced by 60%, while the thermal performance was improved by 10%.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3032-3036
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• 2011

Cooling type of traction motor for EMU in domestic is mostly an open type. Its system is a cooling air entered through air inlet cool down a traction motor and an hot air by traction motor get out air outlet. It is easy to cool it down but hard to maintain it. To improve an ability of maintenance, a total enclosed type traction motor is already developed and used in abroad, not an opne type. So we developed a total enclosed type traction motor which will be used in domestic and abroad EMU. We tried to reduce a weight and a size compared with the abroad one. In contrast with open type traction motors which cool off inside of motors, total enclosed motors cool down by cooling exterior frame of motors. In this case, cooling fins or air fan blowing to the exterior of motors are applied. The total enclosed type traction motor developed by us have two housing to block the foreign substance into inner of a motor and have two cooling fan to easy to reduce a heat happened at a coil. In this paper, design of a cooling structure of the total enclosed traction motor developed twice and performance verification through test will be discussed.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2518-2523
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• 2007

In this paper, thermo-flow characteristics of an outer-rotor type of a BLDC motor are numerically analyzed using three-dimensional turbulence modeling. In an advance design of BLDC motor, cooling blades and holes are preferred for the enhanced cooling performances. Rotating the blades and holes generates axial air flow passing through stator slots, which cools down stator by forced convection. For the present study, a new design of the BLDC motor has been developed and major design parameters such as the arrangement of cooling holes, the area of cooling holes, and cooling blades and the cooling blade angle, are analyzed for the enhanced convective heat transfer rate. It is found that the convective heat transfer rate of the new BLDC motor model is increased by about 8.1%, compared to that of the reference model.

• Transactions of Materials Processing
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• v.25 no.4
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• pp.242-247
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• 2016

CFD simulation with FlowVision^® is used to evaluate the capability of cooling channel in hot press forming dies. Two different types of cooling channels, dry drilled and pocket types are considered for comparison. Two different approaches for simulating cooling channel are considered. One is single-phase velocity calculation for coolant only and the other is multiphase thermal and velocity calculation for die, blank and coolant all together. Both approaches show better cooling performance in pocket type cooling channel. Also both approaches show their own effectiveness in designing cooling channel of hot press forming dies.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.51-54
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• 2003

The continuous casting is primarily a heat-extraction process in which the heat transfer at various cooling zones profoundly influences quality of products. So development of numerical model is necessarily needed for more specific and clear investigations upon heat transfer mechanism at mold and secondary cooling zones. In this study, heat transfer coefficients which shows the characteristic of heat transfer mechanism in mold are calculated for more exact analysis with temperatures measured in bloom mold using optimal algorithm, and finally the validity of cooling conditions at secondary cooling zone which is actually used at field for 30 Ton bloom type continuous casting of 0.187%C is investigated. From the results of solidification analysis, the characteristic of bloom mold shows good agreements with that of previously studies by other authors and optimized cooling conditions for 0.187%C are presented.