• 한국콘텐츠학회논문지
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• 제18권10호
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• pp.425-430
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• 2018

전기자동차 배터리 시스템은 낮은 온도에서 배터리 출력과 수명이 감소하는 문제가 발생한다. 상온 유지를 목적으로 Positive Temperature Coefficient(PTC) 히터가 사용되고 있다. 하지만 PTC 히터는 복잡한 절연구조로 인해 중량이 크다. 중량이 클수록 전기자동차의 연비가 감소한다. 반면에 인덕션 히터는 단순한 절연 구조로 중량 저감에 효과적이며 빠른 온도 상승 특성을 가지고 있다. 따라서 전기자동차용 히터는 인덕션 히터가 적합하다. 인덕션 히터는 LC공진 회로로 구성된다. 정전용량이 클수록 가격과 중량이 상승하기 때문에 인덕턴스를 높여 정전용량을 감소시켜야한다. 또한 인덕션 히터의 주 발열원은 철손이다. 따라서 전자기장 설계 관점에서 인덕턴스 및 철손의 최적화가 중요하다. 본 논문에서는 인덕션 히터 구조 변경에 따른 인덕턴스 및 철손을 다구찌 기법과 유한요소법(FEM) 시뮬레이션을 통해 분석하고 최적화 설계하였다.

• Journal of Trauma and Injury
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• 제26권4호
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• pp.255-260
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• 2013

Purpose: For the treat hypothermia patients, active warming might be needed. In most emergency departments, IV warm saline infusion is used for treatments. However, during IV warm saline infusion, heat loss from the warm saline may occur and aggravate hypothermia. Thus, in this study, we conducted an experiment on conserving heat loss from warm saline by using a simple method. Methods: Four insulation methods were used for this study. 1) wrapping the set tube for the administration of the IV fluid with a cotton bandage, 2) wrapping the set tube for the administration of the IV fluid with a cotton bandage with aluminum foil, 3) wrapping the warm saline bag and tube with a cotton bandage, and 4) wrapping the warm saline bag and tube with a cotton bandage with aluminum foil. Intravenous fluid was preheated to a temperature between $38-40^{\circ}C$. The temperatures of the saline bag temperature and the distal end of the IV administration set were measured every ten minutes for an hour. The infusion rate was 1000 cc/hr, and to obtain an accurate infusion rate, we used an infusion pump. Results: The mean initial temperature of the saline bag was $39.11^{\circ}C$. An hour later, the fluid temperature at the distal end of the fluid temperature ranged from $39.11^{\circ}C$ to $34.3^{\circ}C$. Without any insulation, the initial temperature of the pre-heated warm saline, $39^{\circ}$ had decreased to $34.8^{\circ}C$ after having been run through the 170-cm-long IV administration tube, and after 1-hour, the temperature was $29.63^{\circ}C$. As we expected, heat loss was prevented most by wrapping both the saline bag and the IV administration set with a cotton bandage and aluminum foil. Conclusion: Wrapping both the saline bag and the IV administration set with a cotton bandage and aluminum foil can prevent heat loss during IV infusion in Emergency departments.

• KIEAE Journal
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• 제13권5호
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• pp.89-96
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• 2013

Green roofs can reduce surface water runoff, provide a habitat for wildlife moderate the urban heat island effect, improve building insulation and energy efficiency, improve the air quality, create aesthetic and amenity value, and preserve the roof's waterproofing. Green roofs are mainly divided into three types : intensive, simple-intensive, and extensive. Especially, extensive roof environment is a harsh one for plant growth; limited water availability, wide temperature fluctuations, high exposure to wind and solar radiation create highly stressed environment. This study, aimed at extensive green roof, was carried out on the rooftop of the library at Seoul Women's Univ. from October to November, 2012 and from March to August, 2013. To suggest the most effective vegetation model for biodiversity and heat island mitigation, surface temperatures were monitored by each vegetation model. We found that herbaceous plants of Aster sphathulifolius, Aceriphyllum rossii and Belamcanda chinensis, shrub of Syringa patula 'Miss Kim', Thymus quinquecostatus var. japonica, Sedum species can mixing each other. Among them, the vegetation models including Sedum takesimense, Aster sphathulifolius, Thymus quinquecostatus var. japonica was more effective on the surface temperature mitigation, because the species have the tolerance and high ratio of covering, and also in water. Especially, in the treatment of bark mulching, they helped to increase the temperature of vegetation models. In the case of summer, temperature mitigation of vegetation models were no significant difference among vegetation types. Compared to surface temperature of June, July and August were apparent impact of temperature mitigation, it shows that temperature mitigation are strongly influenced by substrate water content.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.59-60
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• 2020

Large fires continue to spread throughout the building, including the fire in Uijeongbu in 2015, the fire in Jecheon in 2017, and the fire in Miryang in 2018. According to the above fire case investigation, major problems were the fire resistance performance of compartment members such as fire doors, the fire spread due to damage to exterior wall openings, and smoke spread through vertical openings. However, in South Korea, only specification design is implemented for buildings that are not subject to performance design. In addition, the analysis of the fire resistance performance standards of building members in the specification design showed that fire doors were not specified in detail for 60 minutes of insulation performance and 60 minutes of fire resistance performance of E/V doors, limiting the prevention of fire spread. Therefore, the purpose of this research is to prepare measures to prevent the spread of fire by presenting simple transplants for calculating the required fire time according to the architectural design conditions for the performance design of the components of the fire room according to the purpose of use of the front of the building.

• 한국조명전기설비학회지:조명전기설비
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• 제8권4호
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• pp.55-62
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• 1994

본 논문에서는 기존의 펌프나 가스를 이용한 강제유동식 시스템과는 달리 회전원통을 이용한 유동대전현상에 대하여 연구하여, 강제유동식에서의 대전특성과 비교, 분석하였다. 연구결과, 회전원통 시스템에서의 회전원통의 회전속도 및 온도에 따른 유동대전 특성은 강제유동식과 같은 경향을 보여 회전원통 시스템이 유동대전현상을 연구하는데 적합함을 알 수 있었다. 회전원통시스템은 강제유동식에 비하여 실험장치의 기계적 구조가 간단하고, 적은 양의 절연유만이 필요하며, 여러 가지 다른 물질로 실험하기가 비교적 편리하였다. 또한 대전 방지제의 첨가나 절연유의 열화에 따른 대전현상 등을 연속적으로 측정할 수 있는 특징이 있음을 알 수 있었다.

• 수산해양기술연구
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• 제48권1호
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• pp.82-90
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• 2012

Four different buildings having various wall construction are analyzed for the effect of wall mass on the thermal performance and inside building air and wall temperature transient and also for calculating the energy consumption load. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one-dimensional, linear, partial differential equations is obtained using the Laplace transform method, Bromwich and modified Bromwich contour method. A simple dynamic model using steady state analysis as simplified methods is developed and results of energy consumption loads are compared with results obtained using the analytical solution. Typical Meteorological Year data are processed to yield hourly average monthly values. This study is conducted using weather data from two different locations in Korea: Daegu having severe weather in summer and winter and Jeju having mild weather almost all year round. There is a significant wall mass effect on the thermal performance of a building in mild weather condition. Buildings of heavyweight construction with insulation show the highest comfort level in mild weather condition. A proportional controller provides the higher comfort level in comparison with buildings using on-off controller. The steady state analysis gives an accurate estimate of energy load for all types of construction. Finally, it appears that both mass and wall insulation are important factors in the thermal performance of buildings, but their relative merits should be decided in each building by a strict analysis of the building layout, weather conditions and site condition.

• 콘크리트학회논문집
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• 제24권5호
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• pp.535-542
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• 2012

매스 콘크리트에서 발생하는 수화열을 예측하기 위한 단열온도상승시험은 시험 비용이 고가이고 시공간상 제약으로 인해 한계가 있는 실정이다. 이에 신속하고 경제적이며 간편한 간이 수화열 측정 장치의 개발이 필요한 실정이다. 이 연구에서는 간이 수화열 측정 장치를 완성하기 전 단열 성능이 뛰어난 보온병에 콘크리트를 타설하고 열손실량을 보정하여, 간이 수화열 측정 장치의 타당성을 입증하고자 하였다. 열손실량을 정확히 예측하기 위해서는 측정 장치의 정확한 열손실계수를 추정하는 것이 필수적인데, 열손실계수는 단열 장치 내부의 수온 변화를 이용하여 추정하였다. 시험 결과 장치 고유의 열손실계수는 외부 온도와 습도, 내부 온도 변화에 크게 변하지 않는 것으로 드러났다. 실제 단열온도상승시험과 열손실량이 보정된 보온병의 단열온도상승량과의 검증 시험을 통해 이 연구의 객관성과 타당성을 입증할 수 있었다.

• 한국화재소방학회논문지
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• 제19권4호
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• pp.18-25
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• 2005

자연대류유동 형태의 실내화재 해석은 Zone 모델과 Field 모델로 대별된다. Zone 모델은 화염과 연소가스로 인한 상부의 고온 연기층과 하부의 찬 공기층의 온도를 균일하게 간주하고, 실험값을 대입한 간단한 대수식으로 계산하여 간편하나 각각의 위치에 대한 온도와 유속 등을 구할 수 없다. Field모델은 해석영역을 다수의 격자로 구성하고 운동량, 에너지방정식 등을 수치해석하는 방법으로 많은 계산시간 및 컴퓨터 용량이 필요하나 각각의 위치에서의 유동 및 온도분포 등을 자세히 규명 할 수 있다. 열유동 수치해석에는 기존의 상용 프로그램들이 있어 강제대류에는 잘 적용되나, 자연대류에는 대부분 만족할 만한 결과를 주지 못하고 있다. 이에 본 연구에서는 실내화재해석의 기초연구로, 바닥면이 부분적으로 가열될 때 우측벽의 경계조건을 변화시켜 가면서 실내의 층류 자연대류로 인한 유동장과 온도장을 SIMPLE 수치해석방법을 이용하여 직접 수치해석 하였다.

• 교육녹색환경연구
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• 제4권4호
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• pp.19-24
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• 2004

The thermal effect of a transparent insulated opake wall with solar energy was investigated theoretically. The heat gain through transparent insulated opake wall was studied for relative simple conditions. The stationary heat transport effect was studied for layer which is built on the opake wall. This study shows that a relative low solar radiation intensity causes a great heat reduction through the transparent insulated opake wall. Because the transparent insulation layer is mostly transparent to solar radiation, it is opaque to heat radiation.

• 대한기계학회논문집B
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• 제26권5호
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• pp.716-723
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• 2002

Heat transfer in linear motor driven stages for surface mounting device applications was investigated. A simple one-dimensional thermal resistance model (TRM) was introduced. In order to reduce three-dimensional nature to one-dimensional, a few assumptions and simplifications were employed suitably. A good agreement with a finite element heat transfer analysis in temperature profile was obtained. For validation, the analysis was compared with the measurement with respect to motor driving power. Overall discrepancy was less than 7$^{\circ}C$. The influence of two high thermal resistance parts, insulation sheet and thermal contact between the coil assembly and the mounting plate, was examined through the analysis. Additionally, the thermal resistance analysis was applied to another stage including an internal cooling-air passage, and was found available for this system as well. After validation, the cooling effect was surveyed in terms of motor power, and cooling-air and -water flow rate.