• Title/Summary/Keyword: Parabolic system

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Thermal Performance Analysis of Compound Parabolic Collector (CPC) System Employing Storage Tank Through a Year (축열조를 채용한 복합 포물형 태양열 집열기(CPC) 시스템의 연중 열적 성능 해석)

  • LIM, SOK-KYU;JUNG, YOUNG GUAN;KIM, KYOUNG HOON
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.4
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    • pp.376-383
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    • 2019
  • This paper presents of thermal performance analysis by using mathematical models for a compound parabolic collector (CPC) system employing heat storage tank. The thermal performance including insolation energy, heat loss from collector system, useful energy, collector efficiency, and temperature of storage tank were theoretically investigated through a year using monthly-average meteorological data at Seoul. The simulated results showed that the CPC systems are suitable for the applications of higher temperature than flat plate collector (FPC) systems.

Development of Tracking Daylighting System Using Multi-Parabolic Reflector (다중 파라볼릭 반사경 방식을 이용한 추적식 집광시스템 개발)

  • Lee, Chung-Sik;Kim, Jong-Min;Park, Yeon-Min;Sung, Tae-Kyung;Joung, Che-Bong;Kang, Seung-Hoon;Kim, Byung-Chul
    • Journal of the Korean Solar Energy Society
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    • v.33 no.2
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    • pp.56-63
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    • 2013
  • Daylighting system is an alternative lighting system using daylight collecting device, light transformer and light diffuser. In this paper, we developed a daylighting system in which the collecting device composed by dual parabolic reflectors, the silica optical fiber adapted to the light transformer and light diffuser made of the polyglass square sheet. We have estimated the system efficiency and general color rendering index(Ra) of the developed system. The system efficiency measured to 23.8% and Ra was revealed as 95. Ra number of the developed system is bigger than the number(65) of the previous fresnel lens based sunlight collector.

Performance Analysis on Solar Tracking Daylighting Systems Using Different Types of Solar Collectors: Parabolic Dish vs. Fresnel Lens (태양추적식 자연채광 장치의 집광기 종류에 따른 성능 분석: 포물 반사경 vs. 프레넬 렌즈)

  • Kim, Yeongmin;Kim, Won-Sik;Jeong, Hae-Jun;Chun, Wongee
    • Journal of the Korean Solar Energy Society
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    • v.37 no.1
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    • pp.39-45
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    • 2017
  • This paper presents the effect of solar collectors on the performance of solar tracking daylighting systems. A series of measurements were made for two different types of solar collectors mounted on double axis solar trackers: Parabolic dish concentrator and Fresnel Lens. Indoor light levels were measured at different locations of an office space (longitude: 126.33 E, latitude 33.45 N) as photo sensors were placed on a task plane 80 cm above the floor. To accurately monitor the applicability of the systems, measurements were performed under clear and overcast sky conditions with the roll-screen (on the south window) in the down position. Comparing the illuminance data, the system with Fresnel lens outperformed that of parabolic dish concentrator. On clear days, the former delivered the light levels of 400~600 lux on the task plane whereas the latter recorded 100~200 lux. Depending on the amount of cloud cover, on overcast days, illuminance readings fluctuated to some extent.

Near-field Analysis of Dual Parabolic Cylindrical Reflector System for Compact Antenna Test Range (콤팩트 안테나 테스트 레인지용 파라볼릭 원통형 복반사경 시스템의 근접전계 해석)

  • Park, Jae-Hyun;Choi, Hak-Keun;Jeong, Ji-Hoon
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.5
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    • pp.237-244
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    • 2010
  • In this paper, the dual parabolic cylindrical reflector systems are analyzed as the reflector system for the CATR(Compact Antenna Test Range) facility. The near-field at the test zone of the CATR is calculated by using the PO(Physical Optics) approximation. The CATR has to provide an uniform plane wave with the minimum amplitude and phase ripple and the low cross polarization. Therefore, in this paper, the near-field pattern are calculated, and the ripple and taper of the field and the cross polarization are investigated with the position of the subreflector and the test region. It is confirmed that the analysis results can be used for the design of the CATR with the dual parabolic cylindrical reflector.

POLLUTION DETECTION FOR THE SINGULAR LINEAR PARABOLIC EQUATION

  • IQBAL M. BATIHA;IMAD REZZOUG;TAKI-EDDINE OUSSAEIF;ADEL OUANNAS;IQBAL H. JEBRIL
    • Journal of applied mathematics & informatics
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    • v.41 no.3
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    • pp.647-656
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    • 2023
  • In this work, we are concerned by the problem of identification of noisy terms which arise in singular problem as for remote sensing problems, and which are modeled by a linear singular parabolic equation. For the reason of missing some data that could be arisen when using the traditional sentinel method, the later will be changed by a new sentinel method for attaining the same purpose. Such new method is a particular least square-like method which permits one to distinguish between the missing terms and the pollution terms. In particular, a sentinel method will be given here in its more realistic setting for singular parabolic problems, where in this case, the observation and the control have their support in different open sets. The problem of finding a new sentinel is equivalent to finding singular optimality system of the least square control for the parabolic equation that we solve.

Global Attractivity and Oscillations in a Nonlinear Impulsive Parabolic Equation with Delay

  • Wang, Xiao;Li, Zhixiang
    • Kyungpook Mathematical Journal
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    • v.48 no.4
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    • pp.593-611
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    • 2008
  • Global attractivity and oscillatory behavior of the following nonlinear impulsive parabolic differential equation which is a general form of many population models $$\array{\{{{\frac {{\partial}u(t,x)}{{\partial}t}=\Delta}u(t,x)-{\delta}u(t,x)+f(u(t-\tau,x)),\;t{\neq}t_k,\\u(t^+_k,x)-u(t_k,x)=g_k(u(t_k,x)),\;k{\in}I_\infty,}\;\;\;\;\;\;\;\;(*)$$ are considered. Some new sufficient conditions for global attractivity and oscillation of the solutions of (*) with Neumann boundary condition are established. These results no only are true but also improve and complement existing results for (*) without diffusion or impulses. Moreover, when these results are applied to the Nicholson's blowflies model and the model of Hematopoiesis, some new results are obtained.

A PARABOLIC SYSTEM WITH NONLOCAL BOUNDARY CONDITIONS AND NONLOCAL SOURCES

  • Gao, Wenjie;Han, Yuzhu
    • Communications of the Korean Mathematical Society
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    • v.27 no.3
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    • pp.629-644
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    • 2012
  • In this work, the authors study the blow-up properties of solutions to a parabolic system with nonlocal boundary conditions and nonlocal sources. Conditions for the existence of global or blow-up solutions are given. Global blow-up property and precise blow-up rate estimates are also obtained.

ERROR ANALYSIS OF FINITE ELEMENT APPROXIMATION OF A STEFAN PROBLEM WITH NONLINEAR FREE BOUNDARY CONDITION

  • Lee H.Y.
    • Journal of applied mathematics & informatics
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    • v.22 no.1_2
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    • pp.223-235
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    • 2006
  • By applying the Landau-type transformation, we transform a Stefan problem with nonlinear free boundary condition into a system consisting of a parabolic equation and the ordinary differential equations. Fully discrete finite element method is developed to approximate the solution of a system of a parabolic equation and the ordinary differential equations. We derive optimal orders of convergence of fully discrete approximations in $L_2,\;H^1$ and $H^2$ normed spaces.

Design of Concentrating System for Solar Side-pumped Slab Laser

  • Fan, Wentong;Liu, Yan;Guo, Pan;Deng, Rui;Li, Nan;Ding, Fukang;Li, Yasha;Zhou, Jun;Xie, Shiwei
    • Current Optics and Photonics
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    • v.4 no.1
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    • pp.50-56
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    • 2020
  • The design of a concentration system for a solar side-pumped slab laser was investigated. The side size of the slab laser medium is 2 mm × 20 mm. Based on the principle of the edge ray, a secondary concentrating system consisting of a rectangular parabolic mirror (RPM) and a rectangular dielectric-filled compound parabolic concentrator (RDCPC) was demonstrated. The focal length of RPM is 1200 mm and the size is 734 mm × 2000 mm. The outlet size of the RDCPC is 2 mm × 20 mm. The concentration effect was analyzed by using Tracepro optical software. The results showed that the concentration efficiency reached 81.3% and the uniformity of the spot was 91.4% after optimization. This design of concentration system is of great reference value for a solar side-pumped slab laser.