• Title/Summary/Keyword: Cooling Temperature

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Efficacy of Cooling Vest for Auxiliary Body Cooling in Hot Environments(2) - Comparison in Terms of Thermophysiological Properties Between New Cooling Vest and Standard Cooling Vest - (고온환경 하에서 착용하는 인체냉각 보조도구로서의 Cooling Vest연구(2) - 개발제품의 온열생리학적특성 -)

  • Kwon, Oh-Kyung;Kim, Tae-Kyo;Kim, Jin-A
    • Fashion & Textile Research Journal
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    • v.2 no.4
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    • pp.346-352
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    • 2000
  • The purposes of this study are finding out thermophysiological properties throughout wearing experiment with standard cooling vest as well as providing data in order to design and apply more comfortable cooling vest. To do this study, we produced cooling vest newly. 1. Rectal temperature was ascended approximately from $37.2^{\circ}C$ to $38.05^{\circ}C$ in lab, but wearing cooling vest, the temperature was descended 0.2 while wearing developed product compare with existing product. Mean skin temperature which was showed distribution from $32.8{\sim}36.5^{\circ}C$, it was descended $1.0{\sim}1.1^{\circ}C$, while wearing cooling vest and comparing with existing product, wearing developed product was lower $0.5^{\circ}C$. 2. While wearing developed cooling vest, it was found that they had lower tendency than standard cooling vest. Specifically in case of temperature within clothing (chest) $0.2{\sim}2.0^{\circ}C$ in case of humidity within clothing 2~8%RH. Facts from above we confirmed that clothing microclimate had been improved and space was happened between body and garment in order to control. 3. In subjective sensation, standard cooling vest made negative response during experiment period from participants, but new cooling vest was nearing to comfortable area. It was con finned from above conclusions that wearing developed product is more effective in terms of comfort and reduction of heat stress in situation of working in hot environment.

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Effect of Coolant Flow Characteristics in Cooling Plates on the Performance of HEV/EV Battery Cooling Systems (하이브리드/전기 자동차 배터리 냉각 시스템의 냉각수 유동 특성이 냉각 성능에 미치는 영향에 대한 해석적 연구)

  • Oh, Hyunjong;Park, Sungjin
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.3
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    • pp.179-185
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    • 2014
  • Average temperature and temperature uniformity in a battery cell are the important criteria of the thermal management of the battery pack for hybrid electric vehicles and electric vehicles (HEVs and EVs) because high power with large size cell is used for the battery pack. Thus, liquid cooling system is generally applied for the HEV/EV battery pack. The liquid cooling system is made of multiple cooling plates with coolant flow paths. The cooling plates are inserted between the battery cells to reject the heat from batteries to coolant. In this study, the cooling plate with U-shaped coolant flow paths is considered to evaluate the effects of coolant flow condition on the cooling performance of the system. The counter flow and parallel flow set up is compared and the effect of flow rate is evaluated using CFD tool (FLUENT). The number of counter-flows and flow rate are changed and the effect on the cooling performance including average temperature, differential temperature, and standard deviation of temperature are investigated. The results show that the parallel flow has better cooling performance compared with counter flow and it is also found that the coolant flow rate should be chosen with the consideration of trade-off between the cooling performance and pressure drop.

The effect of injection molding cooling parameters on shrinkage of plastic roller (사출성형의 냉각 파라미터가 플라스틱 롤러의 수축에 미치는 영향)

  • Cho, Sung-Gi;Han, Seong-Ryeol
    • Design & Manufacturing
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    • v.15 no.4
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    • pp.8-13
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    • 2021
  • A plastic roller for opening and closing the safety door of the injection molding machine was molded. The dimensional change of the measurement position of the roller was studied when the cooling time was applied differently among the molding conditions, and when the temperature of the coolant applied for mold cooling was also applied differently. Cooling times of 300 seconds and 400 seconds, hot and low-temperature coolant were applied. When the low-temperature coolant was applied, the measuring point of the roller shrank by 0.03 mm. However, when the high-temperature coolant was applied, the measuring point shrank by 0.3 mm. It was found that the application of low-temperature coolant among coolants was more suitable for the reference dimension of the molded article compared to the application of high-temperature coolant. Among the cooling water applied for the molding of plastic rollers, when high-temperature coolant is applied, the shrinkage rate measured immediately after ejection was smaller than when low-temperature coolant is applied. However, it was found that post shrinkage, which occurs over time, occurs much larger when high-temperature coolant is applied.

Small-Capacity Solar Cooling System by Desiccant Cooling Technology (태양열 이용 소용량 제습냉방시스템)

  • Lee, Dae-Young;Kwon, Chi-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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    • pp.154-156
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    • 2008
  • A prototype of the desiccant cooling system with a regenerative evaporative cooler was built and tested for the performance evaluation. The regenerative evaporative cooler is to cool a stream of air using evaporative cooling effect without an inc6rease in the humidity ratio. It is comprised of multiple pairs of dry and wet channels and the evaporation water is supplied only to the wet channels. By redirecting a portion of the air flown out of the dry channel into the wet channel, the air can be cooled down to a temperature lower than its inlet wet-bulb temperature at the outlet end of the dry channels. Incorporating a regenerative evaporative cooler eliminates the need for deep dehumidification in the desiccant rotor that is necessary to achieve low air temperature in the system with a direct evaporative cooler. Subsequently, the regenerative evaporative cooler enables the use of low temperature heat source to regenerate the dehumidifier permitting the desiccant cooling system more beneficial compared with other thermal driven air conditioners. At the ARI condition with the regeneration temperature of $60^{\circ}C$, the prototype showed the cooling capacity of 4.4 kW and COP of 0.75.

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Low Temperature Storage of Rough Rice Using Cold-Air in Winter (II) - Low Temperature Storage Characteristics of Rough Rice Using a Cooling System in the Top of a Bin - (겨울철 냉기를 이용한 벼의 저온저장 (II) - 빈상부 쿨링시스템을 이용한 냉각 벼의 저온저장 특성 -)

  • Lee, Jae-Seok;Hong, Hyun-Ki;Li, He;Park, Jong-Soo;Ham, Tack-Mo;Han, Chung-Su
    • Journal of Biosystems Engineering
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    • v.32 no.1 s.120
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    • pp.13-19
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    • 2007
  • Storage rough rice in low temperature using the winter cold air avoids rough rice temperature increase which happens from early May, and this is possible by installing a cooling system in the top of a bin, the room between top rice level and bin ceiling. The research objective is to establish low temperature rough rice storage technique, furnishing winter cold air to rough rice, by investigating the cooling system potential of maintaining low rough rice temperature and by analyzing rough rice storage characteristics over a storage period. The rough rice storage characteristics were evaluated from January to August 2003, using a storage and dry bin of 400-ton capacity. Results of this research are as follows: Cooling bin using the cooling system in the top of the bin maintained the rice temperature less than 15$^{\circ}C$ in entire portions in August. Moisture contents and germination rates of rough rice were decreased over the storage period, on the other hand, the rough rice stored in the ambient temperature bin had relatively lower moisture contents and germination rates to compare with the bin using winter cold air. Crack ratio and acid value of brown rice in the ambient temperature bin storage had increased more than the cooling bin storage. The result indicates that the storage bin using winter cold air and the cooling system maintains moisture content and germination of rice, minimizes cracked kernel and acid value, and preserves rice quality as well.

Evaluation of Heating and Cooling Thermal Output Characteristics of Prefabricated Steel Wall Panel System for Radiant Heating and Cooling (강판 마감형 조립식 벽패널 복사냉난방시스템의 냉난방 방열 특성 평가)

  • Lim, Jae-Han;Koo, Bo-Kyoung;Kim, Sung-Im;Song, Seung-Yeong
    • Journal of the Korean Solar Energy Society
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    • v.33 no.2
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    • pp.70-77
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    • 2013
  • Recently the radiant panel heating and cooling system has been regarded as an alternative of low temperature heating and high temperature cooling by applying the renewable energy sources to the heating and cooling of buildings. Especially this system can be used as HVAC system alternatives in super high-rise buildings for energy saving and thermal comfort. Also it can be possible to reduce the plenum space because the minimum ventilation air will be supplied into the space. This study focused on the evaluation the basic characteristics of thermal output in prefabricated steel wall panel system for radiant heating and cooling. In order to evaluate the thermal output according to both various supply water temperatures and supply water flow rates, three-dimensional dynamic heat transfer analysis was performed. As results, for the heating mode, thermal output increased by 26% with the supply temperature increasing by $5^{\circ}C$. The surface temperature of panels range within $1{\sim}3^{\circ}C$. For the cooling mode, thermal output decreased by 18.2% with the supply temperature increasing by $2^{\circ}C$. The surface temperature of panels range within $0.5{\sim}1^{\circ}C$ and it was shown the even temperature distribution.

A Study on the Spray Cooling Characteristics of hot Flat Plates (고온평판의 분무냉각특성에 관한 연구)

  • 윤석훈
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.6
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    • pp.880-887
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    • 1998
  • In order to study heat transfer characteristics of spray cooling for the purpose of uniform and soft cooling of high temperature surface a series of experiments for a hot horizontal copper flat plate was performed by downflow spray water using flat spray nozzle. Cooling curves were mea-sured under the various experimental conditions of flow rates and temperatures of cooling water Surface temperature surface heat fluxes and heat transfer coefficients of horizontal upward-facing flat surface were calculated with cooling curves measured at each radial positions near the cooling surface by TDMA method. Generally heat transfer characteristics for spray cooling is simi-lar to boiling phenomenon of pool boiling. The minimum heat flux(MHF) appear at the surface temperature of about ${\Delta}Tsat=250^{\circ}C$ and the critical heat flux(CHF) appear at about ${\Delta}Tsat=250^{\circ}C$.

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Temperature Setpoint Algorithm for the Cooling System of a Tilting Train Main Transformer (틸팅열차 주변압기 냉각시스템의 온도설정알고리즘)

  • Han, Do-Young;Noh, Hee-Jeon;Won, Jae-Young
    • Proceedings of the SAREK Conference
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    • 2008.11a
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    • pp.387-392
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    • 2008
  • In order to improve the efficiency of the main transformer in a tilting train, the optimal operation of a cooling system is necessary. For the development of the optimal control algorithm of a cooling system, the mathematical model of a main transformer cooling system was developed. This includes the dynamic model of a main transformer, an oil pump, an oil cooler and a blower. The system algorithm of a cooling system, which consists of the temperature setpoint algorithm and the temperature control algorithm, was developed. Optimal oil temperatures of the inlet and the outlet of the main transformer were obtained by considering the total electric power consumption of the system. The oil inlet temperature was controlled by the blower and the oil outlet temperature was controlled by the oil pump. A simulation program was developed by using the mathematical model and the system algorithm. Simulation results showed that the system algorithm developed from this study may be effectively used to control the main transformer cooling system in a tilting train.

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Numerical Analysis of Heat Transfer Characteristics of Cooling System for 2.3 kW EV Battery Pack (2.3 kW급 전기자동차 배터리팩용 냉각 장치의 열전달 특성에 관한 해석적 연구)

  • Seong, Dong-Min;Park, Yong-Seok;Sung, Hong-Seok;Suh, Jeong-Se
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.6
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    • pp.44-49
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    • 2022
  • The improvement in the battery performance and life using a battery thermal management system directly affects the improvement in the performance, life, and energy efficiency of electric vehicles. Therefore, this study numerically analyzed the heat exchange processes between the coolant inside the cooling plate channel and the heat generated by the battery. The cooling performance was analyzed based on the average temperature, temperature uniformity, and the maximum and minimum temperature differences of the battery. A performance difference existed depending on the coolant inlet temperature but showed the same tendency of cooling performance according to the shape of each plate's channel. Type 1 showed the best results in terms of battery temperature uniformity, which is the most important measure of battery performance; Type 2 showed the best results in terms of the average temperature of the battery; and Type 3 showed the best results in terms of the maximum and minimum temperature differences of the battery compared with that of the other cooling plates.

The Neural-Fuzzy Control of a Transformer Cooling System

  • Lee, Jong-Yong;Lee, Chul
    • International Journal of Advanced Culture Technology
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    • v.4 no.2
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    • pp.47-56
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    • 2016
  • In transformer cooling systems, oil temperature is controlled through the use of a blower and oil pump. For this paper, set-point algorithms, a reset algorithm and control algorithms of the cooling system were developed by neural networks and fuzzy logics. The oil inlet temperature was set by a $2{\times}2{\times}1$ neural network, and the oil temperature difference was set by a $2{\times}3{\times}1$ neural network. Inputs used for these neural networks were the transformer operating ratio and the air inlet temperature. The inlet set temperature was reset by a fuzzy logic based on the transformer operating ratio and the oil outlet temperature. A blower was used to control the inlet oil temperature while the oil pump was used to control the oil temperature difference by fuzzy logics. In order to analysis the performance of these algorithms, the initial start-up test and the step change test were performed by using the dynamic model of a transformer cooling system. Test results showed that algorithms developed for this study were effective in controlling the oil temperature of a transformer cooling system.