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Dish/Stirling 시스템 적용을 위한 Hybrid 태양열 흡수기의 열특성에 관한 실험 연구
강명철,김진수,강용혁,김낙주,유성연,김진혁,Kang, Myeong-Cheol,Kim, Jin-Soo,Kang, Yong-Heack,Kim, Nack-Joo,Yoo, Seong-Yeon,Kim, Jin-Heack 한국태양에너지학회 2007 한국태양에너지학회 논문집 Vol.27 No.3
A Dish type solar concentrating system consists of a parabolic concentrator and a cavity receiver. In order to achieve high temperatures from solar energy, it is essential to efficiently reflect the solar rays in the concentrator and to minimize thermal losses in the cavity receiver. Improving the economical efficiency of a solar power system required the stirling unit to be operated continuously. For continuous operation of the stilting unit, the receiver must be continuously provided with thermal energy from solar as well as additional combustion heat. It is possible for a hybrid solar receiver system equipped with an additional combustion to be operated 24 hrs/day. A hybrid solar receiver was designed and manufactured for a total thermal load of 35 kW in the operating temperature range $700^{\circ}C$ to $800^{\circ}C$. The hybrid receiver system was tested in gas-only mode by gas-fired heat to investigate thermal characteristics at inclination angle varying from 0 deg to 30 deg(cavity facing down) and the aperture to cavity diameter ratios of 0(closed cavity) and 1.0(open cavity). This paper has been conducted to measure temperature distribution in cavity surface and to analyze thermal resistances, and the evaporation and condensation heat transfer coefficient in all cases(open and closed cavity).
강명철(Kang, Myeongcheol),강용혁(Kang, Yongheack),윤환기(Yoon, Hwanki),유창균(Yu, Changkyun) 한국신재생에너지학회 2005 한국신재생에너지학회 학술대회논문집 Vol.2005 No.06
This experimental study represents the results of an analysis on the characteristics of flux density distribution in the focal region of solar concentrator. The characteristics of flux density distributions are investigated to optimally design and position a cavity receiver. This was deemed very useful to find and correct various errors associated with a dish concentrator. We estimated the flux density distribution on the target placed along with focal lengths from the dish vertex to experimentally determine the focal length. It is observed that the actual focal point exists when the focal length is 2.17m. The total integrated power and percent power was 2467W and 85.8%, respectively, in the case of small dish, and also 2095W and 79%, respectively, in the case of KIERDISH II. As a result of the percent power within radius, approximately 90% of the incident radiation is intercepted by about 0.06 m radius. The minimum radius of receiver in KIERDISH II is found to be 0.15m and approximately 90% of the incident radiation is intercepted by receiver aperture.
강명철(Kang, Myeong-Cheol),강용혁(Kang, Yong-Heack),윤환기(Yoon, Hwan-Ki),유성연(Yoo, Seong-Yeon) 한국신재생에너지학회 2005 한국신재생에너지학회 학술대회논문집 Vol.2005 No.11
To evaluate the performance of concentrating solar cookers, a parabolic solar cooker have been designed and constructed. Tests were carried out to define the performance characteristics of concentrating cookers under ambient conditions. The performance and test of the solar cooker were measured and conducted using the international standard procedure that was proposed at the Third World Conference on solar cooking. Stagnation temperature and water heating tests were carried out to determine the maximum temperature attained by the cooker and to evaluate the thermal performance of the cooker. The analysis showed that the solar cooker has maximum cooking power and efficiency 474W, 420W and 41%, 40%, respectively.
강명철(Kang, Myeong-Cheol),김진수(Kim, Jin-Soo),강용혁(Kang, Yong-Heack),김낙주(Kim, Nack-Joo),유성연(Yoo, Seong-Yeon) 한국신재생에너지학회 2006 한국신재생에너지학회 학술대회논문집 Vol.2006 No.06
To improve economic of solar power generation, stirling engine is required continuous operation and the receiver has to be provided with an additional combustion system. The hybrid receiver with a specially adapted combustion system is possible to 24 hr/day operation by solar and gas-fired. The inner cavity and external wall serve as absorber surfaces using collected irradiation and heat transfer surfaces for the gas heat flow, respectively. The hybrid receiver was designed and fabricated for the dish/stirling system. The analytical method for pridicting natural convective heat loss from receiver is used. The Koenig and Marvin model is used to estimate convection heat loss and heat transfer coefficiency.
접시형 태양열 집광시스템용 흡수기의 자연대류 열손실 수치해석 연구
강명철(Kang, Myeong-Cheol),강용혁(Kang, Yong-Heack),김종규(Kim, Jong-Kyu),김진수(Kim, Jin-Soo),유성연(Yoo, Seong-Yeon) 한국신재생에너지학회 2007 한국신재생에너지학회 학술대회논문집 Vol.2007 No.06
In dish concentrating system, natural convection heat loss occurs in cavity receiver. Heat loss mechanisms of conduction, convection, and radiation can reduce the system efficiency. To obtain the high efficiency, the receiver is to absorb the maximum of solar energy and transfer to the working fluid with maximum of heat losses. The convection heat loss is an important factor to determine the system performance. Numerical analysis of the convection heat loss of receiver was carried out for varing inclinaton angle from 0^{cdot} to 70^{cdot} with temperature range from 400^{cdot}C to 600^{cdot}C using the commercial software package, Fluent 6.0. The result of numerical analysis was comparable with convection heat loss model of solar receiver.
태양열과 가스 연소열을 복합 적용한 흡수기의 열특성 연구
강명철(Kang, Myeong-Cheol),김진수(Kim, Jin-Soo),강용혁(Kang, Yong-Heack),윤환기(Yoon, Hwan-Ki),유창균(Yu, Chang-Kyun),이상남(Lee, Sang-Nam) 한국신재생에너지학회 2006 한국신재생에너지학회 학술대회논문집 Vol.2006 No.11
The Dish/Stirling system with the Stirling engine is currently used to convert solar energy directly to electrical energy successful operation of dish/Stirling system is supported by hybrid system, which will allow continuous operation driven by solar and combustion heat ins. The hybrid Receiver has to be provided with an additional combustion system. The heat pipe receiver and conbustion system were manufactured and tested for thermal characteristics of receiver. Maximum temperature difference along the heat pipe surface is 200?C. Emission measurements showed low NOx values of 28 to 46 ppm and very high CO values of 18 to 201 ppm.
항공기용 터보팬 엔진의 성능변수를 이용한 정비 주기 및 비용 예측에 관한 연구
강명철(Myoungcheol Kang),Stephen Ogaji,Pericles Pilidis,공창덕(Changduk Kong) 한국추진공학회 2008 한국추진공학회 학술대회논문집 Vol.2008 No.5
본 연구에서는 항공기용 엔진의 성능 및 기하학적 데이타를 입력 값으로 하여 창정비 주기 및 비용을 예측할 수 있는 새로운 방법을 제시하였다. 엔진의 순주기비용 중에서 엔진의 성능과 가장 밀접하게 관련된 부분은 연료비용과 정비비용이다. 큰 비중을 차지하는 정비비용의 예측은 경제적인 정비계획을 수립하기 위하여 정확한 예측이 필요하다. 현재 운용중인 상업용 항공기 엔진들의 성능 및 정비 비용 요소 데이터베이스를 구성하여 그 사이의 통계적 관계식을 이용하여 정비비용을 예측하는 연구를 수행하였다. 예측결과는 이전 식들의 결과와 비교하였으며 보다 세밀하고 신뢰성 있는 결과를 얻을 수 있었다. This study presents a detailed analysis of aircraft engine maintenance cost based on the relationships between engine performance and geometric parameters. Some trend equations based on the engine performance and maintenance database were developed for the estimation of shop-visit interval, work-scope, man-hours, material cost and Life Limited Part cost. The results show that this approach can give a more reasonable and detailed estimation of engine maintenance cost than older empirical methods.