urban area by using a smaller number of modules, thus eliminating transmission costs and inefficiencies. Community size power can be generated by integrating this type of plant info newly expanding suburban areas with the possibility of using waste heat for commercial and residential space conditioning. Finally, it is possible to integrate these devices into low rise industrial sites for electric and heat generation. For the purposes of this evaluation, only the central power station application will be considered. 2.1.1 Collector Subsystem In general, a parabolic dish collector with two-axis tracking intercepts the most solar energy per m2 of aperture area compared to all other types of solar collectors. Figure 2 illustrates the relative differences for various types of collectors in their ability to intercept sunlight in June (based on Ref. 1). The parabolic dish with two-axis tracking always makes the maximum use of its collector surface since the dish aperture is perpendicular to the sun over the entire day. Varying atmospheric absorption of the solar input accounts for the variation shown over the day. Each of the other collectors has an additional geometric effect either on a daily or seasonal basis which further reduces the effectiveness of the collector. An artist's sketch of the parabolic dish collector is shown in Figure 3(a). Short insulated ducts carry the heated fluid from the cavity receiver along the strut to the closed cycle Brayton engine. The engine is on the ground adjacent to the base of the collector pedestal (not shown). Figure 3(b) shows the cavity receiver at the focal point where the inert gas is heated to temperatures in excess of 800°C. Although several types of reflection surfaces could be used for the mirror, backsilvered glass has been assumed. This type of reflection surface has both a high reflectivity and long life. The substrate which provides the structural support for the glass can either be steel with a thermal coefficient similar to glass,
RkJQdWJsaXNoZXIy MTU5NjU0Mg==