• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.103-108
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• 2003

In this paper, the current lead for superconducting device is studied by numerical method. The current lead is cooled by surrounded $N_{2}$ gas by natural convection. The heat conduction equation for current lead and boundary layer equation for $N_{2}$ gas must be solved simultaneously. The boundary layer equation for $N_{2}$ gas is highly nonlinear for varied temperature of current lead. So the linearization method is adopted for simplicity. Numerical results using natural convection cooling are compared with the conventional cooling methods such as conduction cooling and vapor cooling methods. The main difference of natural convection cooing is the non-zero temperature gradient at the top of current lead for the minimum heat dissipation into superconducting devices. For the optimized conduction-cooling and vapor-cooling current leads, the temperature gradient at the top of current lead is zero. Also, the heat flow at the cold end is much smaller than conduction cooling case.

• Coupled systems mechanics
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• 제11권1호
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• pp.43-54
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• 2022

In order to analyse the thermal performance of battery systems in electric vehicles complex simulation models with high computational cost are necessary. Using reduced order methods, real-time applicable model can be developed and used for on-board monitoring. In this work a data driven model of the cooling plate as part of the battery system is built and derived from a computational fluid dynamics (CFD) model. The aim of this paper is to create a meta model of the cooling plate that estimates the temperature at the boundary for different heat flow rates, mass flows and inlet temperatures of the cooling fluid. In order to do so, the cooling plate is simulated in a CFD software (ANSYS Fluent ®). A data driven model is built using the design of experiment (DOE) and various approximation methods in Optimus ®. The model can later be combined with a reduced model of the thermal battery system. The assumption and simplification introduced in this paper enable an accurate representation of the cooling plate with a real-time applicable model.

• 한국산학기술학회논문지
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• 제16권6호
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• pp.4253-4259
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• 2015

본 연구에서는 자연외기를 활용하여 건물의 에너지절약을 위한 외기냉방제어 시스템에 대하여 다양한 제어방법에 따른 제어특성 및 에너지 소비량에 미치는 영향에 관해 시뮬레이션 연구를 수행하였다. 연구 방법으로는 TRNSYS 프로그램을 활용하여 시스템 해석 모델링을 수행하였으며, 외기 냉방을 하지 않은 경우와 기존의 외기냉방 제어방법들을 적용하였을 경우에 대해 제어성능에 대한 비교 분석이 이루어졌다. 연구 결과로 외기온도 변화에 따라 적절한 외기도입 온도조건을 선정하는 것이 에너지 절감에 효과적이며, 외기와 환기온도를 비교하여 온도제어하는 방법이 에너지 절감효과가 가장 크게 나타남을 알 수 있었다.

• 한국기계연구소 소보
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• 통권16호
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• pp.117-126
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• 1986

Trouble-free operation of cooling water systems is essential for efficient pro¬duction in most industrial facilities. Improper water treatments frequently cause such problems as corrosion, scaling, fouling and slime formation. Water quality, methods of cooling and materials of construction in the cooling circuit should be carefully studied before making selection of the water treatment programs. This paper reviewed cooling water problems encountered frequently in the open recirculating cooling systems and discussed the counter measures how to cope with them.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권3호
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• pp.297-312
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• 2012

For future multi-core processors, 3D integration is regarded as one of the most promising techniques since it improves performance and reduces power consumption by decreasing global wire length. However, 3D integration causes serious thermal problems since the closer proximity of heat generating dies makes existing thermal hotspots more severe. Conventional air cooling schemes are not enough for 3D multi-core processors due to the limit of the heat dissipation capability. Without more efficient cooling methods such as liquid cooling, the performance of 3D multi-core processors should be degraded by dynamic thermal management. In this paper, we examine the architectural impact of cooling methods on the 3D multi-core processor to find potential benefits of liquid cooling. We first investigate the thermal behavior and compare the performance of two different cooling schemes. We also evaluate the leakage power consumption and lifetime reliability depending on the temperature in the 3D multi-core processor.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.7-11
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• 1999

The recent progress in new cooling techniques of the high Tc superconductor(HTS) systems is reported and discussed with some practical examples. At the beginning stage of the HTS development in research laboratories, liquid nitrogen(LN$_2$) is the standard medium for an effective cooling. The success of HTS in many different application areas, however, has required a variety of need in the cooling temperature and the cooling capacity with specific design restrictions. While the utilization of alternative liquid cryogens such as liquid neon (LNe) or liquid hydrogen (LH$_2$) has been tired in some of them, even solid cryogens such as solid nitrogen (SN$_2$) or solid hydrogen (SH$_2$) may be another option in special applications. The gaseous helium cooled by a cryogenic refrigerator has also been a good candidate in many cases. One of the best cooling methods for the HTS is the direct conduction-cooling by a closed-cycle refrigerator with no cryogen at all. The refrigeration may be based on Joul-Thomson, Brayton, Stirling, Gifford-McMahon, or pulse tube cycles. The pros and cons of the newly proposed cooling methods are described and some significant design issues are presented.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
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• pp.345-350
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• 2000

The heat produced by the fission in the fuel of HANARO, 30 MW research reactor, is transferred from the primary cooling water to the secondary cooling water through heat exchangers, and the heat absorbed by the secondary cooling water is released into the atmosphere by the 33 MW cooling tower which is a mechanical induced draft and counter flow type. If the outlet temperature of cooling tower exceeds 33 of due to the loss of the cooling tower performance under reactor operation above $50\%$ of the full power, the reactor power should be reduced to half of the full power for safe operation. Therefore, the cooling capability of cooling tower should be maintained for the reactor to be normally operated. To predict the capability of cooling tower for full power reactor operation of 30 MW, the performance test of cooling tower was done at the reactor present power of 24 MW and the capability was respectively evaluated by characteristics and performance curves methods in accordance with the Code of Cooling Tower Institute of U.S.A. to confirm the reliability of evaluation. As a result, it was confirmed, through the results of each evaluation, that the cooling capability of cooling tower meets the design required heat load. Also, the equations of the performance and the characteristics curves of the cooling tower, based on the collected data during this performance test, was obtained for developing the calculation program to predict the cooling capability during reactor operation.

• 생물환경조절학회지
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• 제11권2호
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• pp.81-87
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• 2002

근권냉방 방식에 따른 냉방 효율과 토마토 생육 특성을 검토하고자 XL냉수순환, 라디에이타 냉풍, 패드냉풍 및 대조구를 처리한 결과는 다음과 같다. 근권부 냉방온도는 공급수온이 17.8$^{\circ}C$일 때 XL 냉수순환구는 18.$0^{\circ}C$ 라디에이타 냉풍구는 27.2$^{\circ}C$, 패드 냉풍구는 20.3$^{\circ}C$였다. 배지 깊이와 시간대별 평균온도는 XL냉수순환구 22.8~24.7$^{\circ}C$. 라디에이타 냉풍구 22.7~24.2$^{\circ}C$, 패드 냉풍구 20.5~23.2$^{\circ}C$, 대조구 25.9~29.6$^{\circ}C$를 나타내어 냉방처리구가 대조구에 비해 5~6$^{\circ}C$더 낮았다. 토마토의 생육에 있어 엽장. 엽폭은 대조구에 비해 컸으며, 생체중 및 건물중의 경우에서도 비슷한 경향이었다 근활력에 있어 대조구는 45.0ug/g에 비해 근권냉방 처리구는 58.5-62.8 ug/g으로 높았으나. 근권냉방 처리구간에는 큰 차이가 없었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.520-523
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• 2003

In this paper, heatsink design for high power converter is presented. There are many ways of designing heatsink, but air cooling is by far the most used and much more practical than any of the other methods. In this paper, the practical methods of cooling which include the method to reduce a noise and a vibration due to a fan and the method to design a gap resistance and a contact resistance due to mounting force between thyristor and heatsink is proposed. Finally, simulation and experimental results are described to verify validity of the proposed method.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2001년도 학술논문발표회
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• pp.52-57
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• 2001

In order to control hydration heat in mass concrete, pipe cooling method has been widely used. The pipe cooling method leads to the decrease of curing period by lagging materials as well as the decrease of temperature difference between center and surface of mass concrete member, There are two methods in the pipe cooling system, which are open loop system and closed loop system. However open loop pipe cooling system cannot be applied to the mass concrete structures when cooling water supply is difficult. To control hydration heat of high strength mass foundation in the central area of city, closed loop pipe cooling system was developed to solve the cooling water supply. This paper reports the performance results of hydration heat control with closed loop pipe cooling system.