الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
This thesis which concerns with the heat transfer characteristics of solar parabolic trough collectors is divided in to six chapters summarized as follows
A survey on the work published locally and abroad on solar collectors including the solar parabolic concentrators has been done to get complete information on the latest development in solar parabolic concen tra tors Chapter 11 From the above survey, modifications related to the absorber tube-envelope assembly as well as the storage tank were suggested to improve the thermal system efficiency of such type of solar collectors. The proposed modifications include the use of partially insulated round tube absorber, with and without fines, or using a flat plate absorber.
Chapter III A theoretical heat transfer model governing the heat transfer by
free convection from the hot absorber tube to the relatively cool envelope for the three suggestions was developed. It was solved numerically using the so-called SIMPLE method proposed by Patankar. The numerical results were presented graphically and relations between the heat transfer coefficien ts expressed by the Nusselt number and the other system parameters have been accurately correlated, for most of the proposed cases.
Two conduction heat transfer models governing the transfer of
heat through the insulated gap of the absorber annulus and the
cylinder storage tank have been developed and both were solved numerically using the same previous numerical techniq ue. The numerical results were presented graphically and given in correlations of suitable use.
pter V An energy balance model applied for all components of such solar system, namely: working fluid, absorber surface, envelope inner and outer surfaces, and storage tank with its connecting pipes was solved numerically under realistic operating and climatic conditions.
pter VI A sample of the solar results given by the hourly storage tank
temperature and the collector and system efficiencies was presen ted in graphs. The results for the two proposed cases were compared with those for conventional type to show the percent of performance improvement due to applying such modifications. Using a partially insulated absorber leads to an increase of system efficiency by 8% over that collector with non-insulated absorber. A further increase in thermal efficiency amoun ting to 3% was noticed when replacing the partially insulated round absorber by a flat surface one attached from above to an insulated semicircular tube for heating the working fluid.