• 설비공학논문집
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• 제16권11호
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• pp.1051-1059
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• 2004

Two phase thermosyphone loop for electronics cooling are designed and manufactured to test its performance under the partial load and low environment temperature conditions. The thermosyphone device has six evaporators connected parallel for the purpose of cooling six power amplifier units (PAU) independently. The heater modules for simulating PAUs are adhered with thermal pad to the evaporator plates to reduce the contact resistance. There are unbalanced distributions of liquid refrigerant in the differently heated evaporators due to the vapor pressure difference. To reduce the vapor pressure differences caused by partial heating, two evaporators are connected each other using the copper tube. The pressure regulation tube successfully reduces these unbalances and it is good candidates for a field distributed systems. Under the low environment temperature operating condition, such as $-30^{\circ}C$, there may be unexpected subcooling in condenser. It leads the very low saturation pressure, and under this condition there exists explosive boiling in evaporator. The abrupt pressure rise due to the explosive boiling inhibits the supplement of liquid refrigerant to the evaporator for continuous cooling. Finally the cooling cycle will be broken. For the normal circulation of refrigerant there may be an optimum cooling air flow rate in condenser to adjust the given heat load.

• 설비공학논문집
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• 제20권4호
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• pp.230-237
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• 2008

The objective of this paper is to investigate the performance characteristics of a $CO_2$ cooling and water heating system using a twin-rotary compressor with the compression volume ratio of 0.6. The cooling performances of the $CO_2$ heat pump were measured and analyzed with the variations of charge amount, EEV opening, and compressor frequency. In addition, the performance of the combined system including cooling and water heating was also measured and analyzed by varying inlet temperature of the EEV. As a result, the optimal normalized charge and cooling COP in the cooling mode were 0.307 and 2.06, respectively. The application of the water heating into the $CO_2$ heat pump improved the cooling performance over 78% and decreased the EEV inlet temperature by $8^{\circ}C$, which can increase system reliability.

• 전력전자학회논문지
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• 제22권5호
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• pp.414-422
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• 2017

This paper reviews the core technical trends of TESLA EV Motors. The TESLA EV Motors is explosively popular with a considerable recharging infrastructure, a wide 17-[inch] touch display, 417 [HP], and 378 [km] going distance. The object of this study analyzes the body appearance, motor and, battery cooling system, battery arrangement, battery management system, super charging station, power electronics, and induction motor.

• 한국화재소방학회논문지
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• 제10권4호
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• pp.3-12
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• 1996

본 연구에서는 화재 감지 회로 등에 사용되는 ZnO 바리스터의 제조과정중 냉각 속도가 전기적 특성에 미치는 영향에 대하여 조사한 것이다. 냉각 속도의 변화에 따른 시편의 미세구조, 전압-전류 특성, 복합임피던스 측정을 하였다. 냉각 속도 $200^{\circ}$/h에서 비오옴계수나 바리스터 동작 전압의 최대치를 나타내었다. 이것은 냉각과정 중 형성된 결정입계에 성질에 의존됨을 알았다. 복합임피던스는 100Hz-13MHz의 주파수 범위에서 측정하였으며, 반원의 특성을 검토한 결과 결정립이나 결정입계의 저항이 냉각 속도에 크게 의존되고 있음을 확인하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.483-486
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• 2006

The fan is widely used to cool high heat flux generated as of the electronic communication device consoles. It, however, makes a lot of noises that interfere considerably with the operation environment. This study was conducted to obtain the cooling design technology of the consoles through being equipped with the Heat Pipe Heat Exchangers (HPHE) together with low revolution fans in place of existing fans for the cooling technology of the forced convection. Not only the sealed type consoles but the HPHE were also designed so as to cool effectively the heat generated from the inside of the console. The simulation was conducted by computational numerical analysis along with its experiments. The results of the numerical analysis and experiments were compared in order to improve the cooling technology of the consoles mounted with the HPHE. Consequently, instead of loud fan noise generated as of existing forced convection methods, the cooling technology of HPHE can remarkably improve many problems such as the operation environment, indoor dust, malfunction caused by pollution sources and so on.

• 한국응용과학기술학회지
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• 제31권3호
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• pp.402-407
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• 2014

Herein, we describe the effect of the cooling-off condition of a solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) film on its molecular distribution and the resultant electrical properties. Since the solvent in a TIPS-pentacene droplet gradually evaporates from the rim to the center exhibiting a radial form of solute, for a quenched case, domains of the TIPS-pentacene film are aboriginally spread showing original features of radial shape due to suppressed molecular rearrangement during the momentary cooling period. For the slowly cooled case, however, TIPS-pentacene molecules are randomly rearranged during the long cooling period. As a result, in the lopsided electrodes structure proposed in this work, the charge transport generates more effectively under the case for radial distribution induced by the quenching technique. It was found that the molecular redistribution during the cooling-period plays an important role on the magnitude of the mobility in a solution-processed organic transistor. This work provides at least a scientific basis between the molecular distribution and electrical properties in solution-processed organic devices.

• 전자공학회논문지 IE
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• 제46권4호
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• pp.25-30
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• 2009

용광로는 외피 부분에 내부 내화물의 온도를 낮추기 위하여 냉각수를 공급하는 냉각판 또는 스테이브를 사용하고 있다. 주변 조업 조건의 열악으로 냉각수를 공급하는 배관의 부식으로 냉각수가 내화물에 침투하여 내화물의 수명을 떨어뜨리고, 노황을 악화시키는 원인이 되고 있다. 이에 본 연구는 용광로 냉각설비장치에 이상 현상이 발생하였을 때 위치를 정확히 확인함에 따라 신속하게 누수된 부위를 파악하여 대처할 수 있는 기능을 갖춘 냉각관 누수 자동감지장치를 개발하였다. 주된 연구는 전자제어 장치인 마이크로프로세서를 응용한 전자변 제어장치를 이용하여 냉각설비의 파손으로 발생되는 누수현상으로 인한 고열과 분진 일산화탄소 등의 산출로 작업환경의 재해를 자동방지 하고자 하였으며, 작업환경이 친환경적이며 작업의 가치를 재창출할 수 있는 방법들이 연구되고 있다. 용광로 분위기의 일산화탄소 자동 감지장치와 그에 따른 출력신호를 자동 전송하는 무선중계기 장치를 개발함으로 용광로 냉각설비 장치의 분위기 작업환경을 수동방식에서 무인자동화방식으로 개선하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.367-370
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• 2009

Recently, ultra high strength products can be manufactured by the hot press forming process of Boron steel in automotive and electronics industries. In order to get high strength, the hot press forming should be accompanied by quenching process inducing phase transformation. In the study, the heat conductive die and the cooling channel were designed by the numerical simulation and the effect of three different parameters were determined to improve cooling characteristics.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.429-432
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• 1999

In this paper, we propose a method to improve Genetic Algorithm using Boltzmann selection which Michael has suggested. But Michael uses temperature schedule(the initial temperature, the cooling rate), which can be applicable only to the limited range of problems. We propose a new method to find the critical temperature and the cooling rate as parameters of the temperature schedule. The critical temperature can be derived from the distribution of each individual＇s fitness. Through the application of the island model where each island has differing cooling rate, it is proved that it is unnecessary to find the optimal cooling rate. The simulation on the TSP＇s with various city sizes proves the proposed critical temperature correct.

• 한국전산유체공학회지
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• 제14권1호
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• pp.62-69
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• 2009

The cooling system for electric devices of hybrid vehicles is examined. The present system is composed of coolant paths, inlet diffuser and heat sinks whose shapes are diamond and circular. In this work, inlet duct and fin arrays are combined in proposed models and examined by numerical calculations. Nusselt number and Reynolds number are considered for heat transfer performance. Main focus lies on the looking for optimal model for the cooling system adopted to compact driving module of a hybrid vehicle. The optimal model shows uniform flow patterns in the inlet diffuser and secondary flows after the fins attached to heat source. It is found that the vortical flows around the heat sinks are effective for heat removal mechanism.