Analysis of a fixed spherical reflector exposed to oblique incident rays
TL;DR: In this article, a fixed spherical reflector tracking absorber solar collector, popularly known as fixed mirror distributed focus (FMDF) collector, is described and an analysis has been performed to study the variations in optical concentration along the absorber.
About: This article is published in Energy Conversion and Management.The article was published on 1986-01-01. It has received 4 citations till now. The article focuses on the topics: Reflector (antenna).
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TL;DR: In this article, a theoretical investigation is made for the problem of electromagnetic field focussing by wide angle spherical reflector receiving obliquely incident plane waves of linearly polarized monochromatic radiation.
Abstract: A theoretical investigation is made for the problem of electromagnetic field focussing by wide angle spherical reflector receiving obliquely incident plane waves of linearly polarized monochromatic radiation. The Maslov's method has been applied to determine the electromagnetic fields in the caustic region of the reflector. High frequency field expression which contains caustic region is converted into caustic free field expression by transforming the situation into hybrid domain. The high-frequency field solution that contains the caustic region is obtained from geometrical optics. The defect in high frequency solution due to geometrical optics is overcome by Maslov's method. Two cases of polarization of the incident wave have been considered, namely, (1) with the field parallel and (2) perpendicular to the meridional plane of incidence. The numerical computations are made to study the behavior of field intensity in caustic region using Maslov's method. The analytical and numerical results obtained from Maslov's method are also compared with method of angular spectrum which are in agreement.
8 citations
01 Jan 2012
TL;DR: A field study of a solar bowl operating under Malaysian tropical condition is presented in this article, where a total of 40 days data was collected over a period of four months and the solar bowl was capable of concentrating high amount of heat during solar noon up to about ± 20 o zenith angular deviation.
Abstract: Results of a field study of a solar bowl operating under Malaysian tropical condition are presented. A total of 40 days data was collected over a period of four months. The solar bowl was capable of concentrating high amount of heat during solar noon up to about ± 20 o zenith angular deviation. The maximum temperature achieved was more than 200 o C. For global irradiance of less than 400 W/m 2 , the temperature developed along the receiver was less than 100 o C. A correlation between the concentration ratio and the slope of the temperature-direct irradiance curve is presented which indicates that a high concentration solar collector has better potential in tropical area at the sampling time. The simulated maximum concentration ratio was 95 and together with the empirical observation, solar bowl concentrator should be able to produce power under Malaysian tropical climate.
5 citations
Cites background or result from "Analysis of a fixed spherical refle..."
...Temperature gradients presented by the thermographic images and 3-D diagrams were in good agreements with literatures [4, 8-11] and available experimental data....
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...investigate the characteristic and performance of solar bowl system [2-4, 7-12]....
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TL;DR: In this paper, the optical characteristic of a fixed mirror distributed focus (FMDF) solar collector is used as a basis for the design of an hybrid thermal and photovoltaic (PV) receiver.
4 citations
01 Jan 2012
TL;DR: A numerical simulation of UPM solar bowl is presented in this paper, where the influence of the tropical clear sky irradiance on the collector was numerically studied, whereas the collector performance in time domain was also quantified.
Abstract: A numerical simulation of UPM Solar Bowl is presented in this paper. The numerical analysis considered a general model of solar bowl, which was divided into three modules:(a) reflection characterisation of the bowl, (b) solar flux density along the receiver, and (c) radiation contour mapping of the receiver. The governing equations are resolved in a segregated manner using Matlab programming environment. The influence of the tropical clear sky irradiance on the collector was numerically studied, whereas the collector performance in time domain was also quantified. Single reflection is a major element in thermal concentration. It was observed that solar flux density of collector substantially deteriorated during off
solar noon hour, in which during 08:00 and 16:00 under clear sky of tropics, the percentage reduction of flux density is over 82% at all points of the receiver. The simulated radiation contour mapping of the receiver supports the finding. Other results of the UPM Solar Bowl simulation model are also shown and discussed.
3 citations
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TL;DR: In this article, the Stationary Reflector/Tracking Absorber (SRTA) solar system is analyzed with the aim of combining with it photovoltaic (PV) generation.
Abstract: The Stationary Reflector/Tracking Absorber (SRTA) solar system, which has been described and used in the past for heat and steam generation, is analyzed with the aim of combining with it photovoltaic (PV) generation. The light concentration function along a finite size absorber is calculated. The areas of the absorber which may be unilluminated during parts of the day are determined. It is shown that for a system to be useful for PV generation, the absorber must turn one side toward the outside perimeter of the reflector while tracking, and its diameter must increase with the distance from the reflector. A special two-section polygonal cone is shown to give an approximately constant light concentration along most of its length, and can therefore be used with an array of solar cells of one type only. Such a design also contributes to an incidence angle of the reflected light rays on the absorber surface that is closer to normal than with a cylindrical shape. It is also shown that the length of a real absorber is always shorter than that of an ideal line absorber of zero radius, and that only about 50 percent of the area should be covered with cells, withmore » the rest to be used for thermal absorption and heat generation only.« less
12 citations
TL;DR: To calculate the absorber dimensions for a fixed spherical solar collector, an optical simulation of the raytracing type is proposed and fluctuating points of high flux and permanent zones which receive double and triple reflection rays have been studied.
Abstract: To calculate the absorber dimensions for a fixed spherical solar collector, an optical simulation of the raytracing type is proposed. The physical quantities, which have an effect upon these dimensions, are described as well as the measurement methods. Once the dimensions are determined, the incident flux on the absorber surface can be calculated by the same program in terms of different zenith distances. These calculations can be checked by comparing the calculated flux on the surface of the absorber with the measured flux at different points along the absorber aimed at the full moon instead of at the sun. Through the data obtained from the measurements, fluctuating points of high flux and permanent zones which receive double and triple reflection rays have been studied.
11 citations