A novel investigation approach on technology integration
(Compound parabolic concentrators, pyramid, and single slope
solar stills) was focused for process efficiency augmentation. The
basins of the tubular stills receive radiation due to their direct
exposure to the sun, focusing of direct radiation from the CPC and
some part of reflected diffuse radiation from the CPC. Because the
basins are black, the vast majority of this radiation is converted into
thermal energy, and this heat flows to the water, air and glass tubes.
Hence there is a temperature gradient between different parts of
the tubular still as shown in Fig. 15(a, b). When the tubes are not
cooled by water, the temperature levels are higher in all the parts
(Fig. 15(a)). The maximum water temperature was observed as
95 C, the maximum air temperature was 80 C with maximum
outer cover temperature of 54 C. Due to continuous extraction of
heat by the cooling water circulated through the annulus space of
the receiver tube, the water and inner tube temperatures are
comparatively low throughout the day. The cooling water exit
temperature is almost equal to inner glass tube temperature. The
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