• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.159-168
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• 1997

본 연구는 Moss형 LNG선박의 방열구조에서 LNG탱크에 침입하는 열량과 선체의 온도분포를 예측하고, 운항 중 LNG탱크를 Cooling down(예냉)하는 경우 발생하는 비정상상태에서 LNG탱크에 발생하는 국부적인 열응력을 검토할 수 있는 비정상 온도분포해석과 LNG증발량을 검토하였다. 특히 운항 중인 선박을 대상으로 일반적인 수치계산시에 필요한 각종 입력절차를 간소화 하고 경계조건 선정시에 비 전문가도 쉽게 이용할 수 있는 전산프로그램을 개발하였다. Moss형 LNG탱크의 예냉작업에 필요한 최적의 냉매량과 예냉조건을 비정상상태에서 해석한 것은 설계자 및 선박 운항자에게 유용하게 이용될 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.854-855
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• 2013

최근 국내 전력공급 문제에 따라 다양한 에너지절감형 기술과 제품이 연구되고 있다. 특히 국내 기준 전체 전력 소비량의 약 20%를 차지하는 조명분야에서는 기존 조명을 대체할 친환경, 고효율 LED 조명에 대한 기술이 대두되고 있다. LED 조명은 원리의 특성상 광효율과 비례하여 LED 접합부 온도가 상승하며 이는 광효율과 수명을 저하시킨다. 이에 다양한 방열기술이 LED 조명기술의 핵심이라 할 수 있다. 본 논문에서는 LED 모듈 접합부의 발열을 열전소자를 활용하여 열전발전 함으로써 에너지를 절감하고, 열회수를 통한 방열효과를 제공 하는 LED 조명을 제안한다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.429-430
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• 2014

본 논문에서는 3-레벨 NPC 방식을 적용한 직류배전전력변환장치의 IGBT손실을 고려한 방열을 제안하였다3-레벨 양방향 인버터의 경우 dv/dt가 작기 때문에 THD를 감소 시킬 수 있으며 필터의 부피와 EMI를 저감 시킬 수 있는 장점이 있다. 3-레벨 양방향 인버터에서 Dual-IGBT를 사용할 경우 IGBT의 열분배가 중요하다. 강제 풍냉식 전력변환장치의 신뢰성과 안전성을 높일 수 있도록 IGBT 손실로 인한 발열과 방열을 정확히 분석하고, 시뮬레이션을 통하여 확인하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1027-1032
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• 2013

LED is standing in the limelight as a light part of the low-carbon green energy. While LEDs are eco-friendly, efficient and durable, extreme heat rises can cause their durability to decrease, with 80% of the power supply being turned into heat energy. Heat radiation systems are important because rising temperatures affect the lifetime of LED elements. Therefore, in this paper, thermal analysis was performed for the shape of heat sink to the LED bulb. Also, it is applied the temperature control systems to our products for optimal performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.11
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• pp.1087-1093
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• 2010

The satellite thermal control H/W composed of two parallel channels working for heat pipe (HP) and phase change material (PCM) is suggested for the high heat dissipating component which works intermittently with short duty. In a limited point of view, the HP-PCM device is a kind of off-the-shelf component that requires no dedicated configuration and thermal designs to PCM. Therefore, it can be used with less impact on the program cost and schedule different from most of the PCM applications. In present study the typical honeycomb structure radiator applying the HP-PCM device is designed and the detail thermal math model is developed for numerical analyses. The result comparison between without and with PCM shows that the HP-PCM device redistributes the peak heat around the whole mission period through the alternate melting and freezing of PCM, and, as a result, the maximum and minimum temperatures are effectively alleviated. The drawback of PCM application due to low thermal conductivity can be successfully resolved by means of parallel arrangement of HP channel.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.12
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• pp.1185-1192
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• 2012

The typical operating temperature of an automotive fuel cell is lower than that of an internal combustion engine, which necessitates a refined strategy for thermal management. In particular, the performance of the cooling module has to be higher for a fuel cell system because the temperature difference between the fuel cell and the surrounding is lower than in the case of the internal combustion engine. Even though the cooling system of an automotive fuel cell determines the operating temperature and temperature distribution of the fuel cell, it has attracted little research attention. This study presents the mathematical model of a cooling system for an automotive fuel cell system using Matlab/$Simulink^{(R)}$. In particular, a radiator model is developed for design optimization from the development stage to the operating stage for an automotive fuel cell. The cooling system model comprises a fan, pump, and radiator. The pump and fan model have an empirical relation, and the dynamics of the pump and fan are only explained by motor dynamics. The basic design study was conducted, and the geometric setup of the radiator was investigated. When the control logic was applied, the pump senses the coolant inlet temperature and the fan senses the coolant out temperature. Additionally, the cooling module is integrated with the fuel cell system model so that the performance of the cooling module can be investigated under realistic operating conditions.

• Smart Media Journal
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• v.11 no.9
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• pp.21-29
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• 2022

Ultra Violet(UV) is gradually being replaced with LED instead of general UV lamps. However, the light efficiency of UV LED is still lower than that of the general lamp, and the light efficiency is also low. Due to the current environment and technical problems of UV lamps, the LED replacements are gradually being made. In this study, a new package design and analysis were performed to increase the lifetime and performance of UV LEDs. A new packaging for UV LED were designed and implemented. The new packaging for UV LED was constructed to improve light efficiency. And the electrical and optical characteristics were analyzed respectively. To improve the optical efficiency in UV LED package, the Al has been used based on high reflectivity and applying the optimal lens focusing. Compared to the existing silver Ag, the light efficiency was improved by about 30% or more, and it was confirmed that the light output degradation characteristic was improved by about 10% in the newly applied optical device chip.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.10 s.241
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• pp.1139-1147
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• 2005

The shape optimal design of the plate-fin type heat sink with vortex generator is performed to minimize the pressure loss subjected to the desired maximum temperature numerically. Evaluation of the performance function, in general, is required much computational cost in fluid/thermal systems. Thus, global approximate optimization techniques have been introduced into the optimization of fluid/thermal systems. In this study, Kriging method Is used to obtain the optimal solutions associated with the computational fluid dynamics (CFD). The results show that when the temperature .rise is less than 40 K, the optimal design variables are $B_1=2.44\;mm,\;B_2=2.09\;mm$, and t=7.58 mm. Kriging method can dramatically reduce computational time by 1/6 times compared to SQP method so that the efficiency of Kriging method can be validated.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.120-127
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• 2013

Hybrid electric vehicles have applied electric parts for saving fuel consumption and reducing levels of environmental pollution. Electrification of automobiles is indispensable for entering into global market because of enhanced environment restriction. ISG (Integrated Starter & Generator) system is one of main electric parts and can improve fuel efficiency more than other components by using Idle Stop & Go function and regenerative braking system. However, if ISG motor and inverter work under the continuously high load condition, it will make them the decrease of performance and durability. So the ISG motor and inverter need to properly design the cooling system of them. In this study, we suggested the enhancement points by modifying the thermal design of ISG motor and then confirmed the improvement of the cooling performance.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.836_837
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• 2009

PC용 냉각장치의 일환으로 CPU의 외벽에 방열판을 달고 열전냉각모듈을 설치한 후 방열판을 냉각하기 위해서 펌프를 적용한 수냉식 냉각 시스템을 개발하고자 하였다. 먼저, 냉각 시 펌프의 부하를 설계하고 그 용량에 적절한 저소음, 고효율 BLDC 모터를 개발하고자, 상용화된 외국제품인 S사의 저효율 단상 BLDC 모터가 적용된 수냉식 펌프를 기준으로 하였다. S사의 단상 BLDC 모터에 대한 시뮬레이션과 테스트를 통해서 거의 비슷한 결과를 얻었으며, 이를 이용하여 단가가 다소 상승하더라도 효율과 성능을 향상시킬 수 있는 3상 BLDC 모터구조로 설계를 하였으며, 그 결과 효율이 거의 2배 향상되며 출력 또한 향상됨을 시뮬레이션으로 구현하였다.