• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.246-249
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• 2007

In numerical analysis for phase change material, numerical values of thermodynamic properties such as temperature, pressure, specific volume, enthalpy and entropy are required. But the steam table or diagram itself cannot be used without modelling. In this study applicability of neural networks in modelling superheated vapor region of water was examined by comparing with the quadratic spline. neural network consists of an input layer with 2 nodes, two hidden layers and an output layer with 3 nodes. Quadratic spline interpoation method was also applied for comparison. Neural network model revealed smaller percentage error to quadratic spline interpolation. From these results, it is confirmed that the neural networks could be powerful method in modelling the superheated range of the steam table.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.610-616
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• 2020

This study conducted joint research with the Navy logistics command ship technology research institute to resolve the occurrence of naval vessel's high-temperature warning and equipment shutdown caused by VRTU overheating during summer operation and the dispatch of troops to equatorial regions. The cooling effect was checked according to the installation of a thermoelectric device cooling system, and heat flow and heat transfer characteristics inside VRTU was analyzed using Computational Fluid Dynamics. In addition, the temperature distribution inside the engine room was assessed through interpretation, and the optimal installation location to prevent VRTU overheating was identified. As a result, the average volume temperature inside the VRTU decreased by approximately 10 ℃ with the installation of the cooling system, and the fan installed in the cooling system made the heat circulation smooth, enhancing the cooling effect. The inside of the engine room showed a high-temperature distribution at the top of the engine room, and the end of the HVAC duct diffuser showed the lowest temperature distribution.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.169-170
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• 2006

대형화, 고압화되고 있는 전력설비는 사고가 발생할 경우 그에 수반되는 산업, 경제, 사회적인 손실의 규모가 매우 커지는 경향을 가진다. 특히 적정온도 이상에서의 운전은 전력설비의 오동작을 일으키는 주요한 원인 중 하나이므로 비정상적인 온도상승을 조기에 감지하여 사고의 가능성을 감소시키는 시스템의 개발은 안정적인 전력설비 운용에 반드시 필요한 요소기술이다. 기존의 감시 시스템은 대부분 여러 위치의 정보를 동시에 얻기 위하여 여러 개의 개별 센서를 배열하여야하므로 대형중량화가 불가피하다는 단점을 갖고 있다. 그러나 광섬유 FBG 온도센서는 전자기 간섭의 영향을 받지 않고, 여러 개의 센서를 하나의 광섬유 라인에 설치하여 동시에 여러 부위의 온도를 측정할 수 있는 준분배형 온도센서 구현이 가능하다는 장점으로 과열감시 시스템에 적합한 센서로 인식된다. 본 연구에서는 광섬유 FBG 온도센서를 이용하여 변압기 단락시험을 통해 변압기의 온도 변화를 T-type thermocouple(이하 TC)과 동일한 지점에서 측정하고, 그 데이터를 비교분석함으로써 광섬유 FBG 온도센서 시스템의 신뢰성을 검증하였고, 이를 전력용 변압기 과열감시 시스템으로 적용할 수 있음을 제시하였다.

• Journal of Korean Institute of Fire Investigation
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• v.6 no.1
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• pp.37-41
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• 2005

본 실험은 화재현장에서 발견된 소훼된 전기다리미 내부 바이메탈 스위치 접점이 꺼짐 상태로 식별되는 경우와 다리미에 접촉된 바닥재가 소실 상태로 발견되는 경우의 과열 출화흔을 확인키 위해 조건별 A, B, C로 구분하여 실험한 결과 사용중인 전기 다리미를 면셔츠 위에 1시간 정도 방치한 정도로는 자체 과열 발화할 가능성은 희박한 것으로 판단되었고, 내부 안정장치(바이메탈 스위치, 온도휴즈 등)를 제거하여 자체과열 시킨 다리미의 경우 외부 화염으로 소훼시킨 다리미에 비해 발열선 주변과 발열판 바닥이 심하게 용융된 특징점을 발견하였으나, 실험의 조건상 바닥재 탄화소실정도에 대한 과열 특징점은 명확히 구분치 못하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.685-690
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• 2008

In numerically evaluating the thermal performance of the heat exchanger, numerical values of thermodynamic properties such as temperature, pressure, specific volume, enthalpy and entropy are required. But the steam table or diagram itself cannot be directly used without modelling. In this study the applicability of neural networks in modelling superheated water vapor was examined. The multi-layer neural networks consist of an input layer with 2 nodes, two hidden layers with 15 and 25 nodes respectively and an output layer with 3 nodes. Quadratic spline interpolation was also applied for comparison. Neural networks model revealed smaller percentage error compared with spline interpolation. From this result, it is confirmed that the neural networks could be a powerful method in modelling the superheated water vapor.

• Korean journal of food and cookery science
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• v.30 no.3
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• pp.317-324
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• 2014

This study attempted to investigate the optimum cooking conditions of chicken breast fillets employing the superheated steam (SHS). The effects of SHS cooking conditions on the physico-chemical and sensory properties of chicken breast fillets were studied. Chicken breast fillets for SHS cooking were treated in six different combinations of steam temperature ($330^{\circ}C$ or $350^{\circ}C$) and cooking time (6, 8 and 10 min). As a result, when the chicken breast fillets were cooked for 8min at $330^{\circ}C$ and 6 min at $350^{\circ}C$ steam, the internal temperature of the chicken breast fillets reached $75{\sim}76^{\circ}C$. At that cooking condition, the chicken breast fillets demonstrated lower cooking loss, higher moisture content, lower hardness and fracturability, and higher springiness; further, they had more acceptable sensory properties compared to the other SHS conditions and conventional electric oven cooking (control). These results suggest that the application of SHS technology to chicken breast fillet products can reduce the cooking time and cooking loss; moreover, it can produce highly preferred chicken products compared to conventional electric oven cooking.

• Journal of the Korean Institute of Gas
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• v.14 no.1
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• pp.1-7
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• 2010

In this paper, cycle performance analysis of $NH_3-CO_2$(R717-R744) two-stage cascade refrigeration system is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include subcooling and superheating degree, compressor efficiency, and condensing and evaporating temperature in the ammonia(R717) high temperature cycle and the carbon dioxide low temperature cycle. The main results were summarized as follows : The COP of two-stage cascade refrigeration system increases with the increasing subcooling degree, but decreases with the increasing superheating degree. The COP of two-stage cascade refrigeration system decreases with the increasing condensing temperature, but increases with the increasing evaporating temperature. And the COP of two-stage cascade refrigeration system increases with increasing the compressor efficiency. Therefore, superheating and subcoolng degree, compressor efficiency, and evaporating and condensing temperature of $NH_3-CO_2$(R717-R744) two-stage cascade refrigeration system have an effect on the COP of this system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2565-2571
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• 2009

In this paper, cycle performance analysis of cascade refrigeration system using $NH_3-CO_2$(R717-R744) is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include subcooling and superheating degree and condensing and evaporating temperature in the ammonia(R717) high temperature cycle and the carbon dioxide low temperature cycle. The COP of cascade refrigeration system increases with the increasing superheating degree, but decreases with the increasing subcooling degree. The COP of cascade refrigeration system increases with the increasing condensing temperature, but decreases with the increasing evaporating temperature. Therefore, superheating and subcoolng degree, evaporating and condensing temperature of cascade refrigeration system using $NH_3-CO_2$ have an effect on the COP of this system. A multilinear regression analysis was employed in terms of subcooling, superheating, evaporating, condensing, and cascade heat exchanger temperature difference in order to develop mathematical expressions for maximum COP and an optimum evaporating temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5832-5837
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• 2011

In this paper, we designed a thermal shutdown block for LED applications using a 1 ${\mu}m$ CMOS process. The proposed thermal shutdown protection circuit has been designed with a shut-off temperature of $120^{\circ}C$ and a restart temperature of $90^{\circ}C$ which are suitable conditions for LED driver IC. Also, we got SPICE simulation results of the circuit about process variation of the semiconductor fabrication. From simulation data, process variation rate of the proposed circuit are within 7 % which are good results compared with conventional BJT current mirror type circuit. Finally, we confirmed that the thermal shutdown circuit has good thermal protection function within a LED driver IC.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.207-214
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• 1999

카세트식 이동식부탄연소기의 사고는 과열에 의한 화재뿐만 아니라 접합용기의 파열에 따른 피해가 더 큰 위험성을 내포하고 있다. 접합용기의 파열원인은 화재에 의한 파열과 접합용기 장착 불량에 의한 가스누출로 화염에 의한 파열, 그리고 과대 조리기구를 사용하여 조리기구 및 화염에서 발생되는 열이 접합용기에 전달되어 온도상승에 따른 파열로 구분된다. 현재 카세트식 이동식부탄연소기의 조리기구 크기에 따라 과열에 따른 정확한 검증이 부족하며, 사용자에게 사용장소와 조리기구외 크기만 권고하고 있어 이에 대한 자료가 필요하다. (중략)