THE IMPORTANCE AND EFFECT OF CONFIGURATIONAL GEOMETRY IN THE DESIGN AND APPLICATION OF SOLAR COLLECTORS AND CONCENTRATORS pp.229-252
Authors: (Reccab Ochieng M and Frederick Onyango N, Department of Physics and Materials Science, Maseno University, Maseno, Kenya)
Abstract: The geometric configuration of most if not all solar collectors and concentrators have symmetries which allows them to collect and concentrate solar thermal energy. Since solar collector and concentrator surfaces are normally planes or curves of specific configurations, the analysis of system processes can be carried out through the use of the laws and rules of optics. Because of the known geometries and symmetries found in the collectors and concentrators, analysis of the collection and reflection of light, hence radiation can also be done using configurational geometries of the systems. We discuss the general principles of operation of solar collectors and concentrators then show by means of examples innovative ideas of designing solar collectors and concentrators using the method of configurational geometry. Using two examples, we show the importance and effect of configurational geometry on the Geometric Concentration Ratio, g CR , defined as the area of the collector aperture a A , divided by the surface area of the receiver, a A . We show that for given dimensions of a specific solar collector and concentrator system, (a modified cone concentrator and a modified inverted cone concentrator), the configurational geometries give different concentration ratios unless certain conditions are prescribed. We also demonstrate that different new elements and components in well known configurational geometries can improve the performance of collectors and concentrators. The improvement is given in terms of increase in the geometric concentration ratio, g CR . and the brightness concentration ratio, o CR , defined as the average irradiance (radiant flux) ( r I ) integrated over the receiver area ( r A ) divided by the insolation incident on the collector aperture.