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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Stitch weld effect on solar collector efficiency factor

Lo, Andy Ka-Ming January 1985 (has links)
The thermal effects of stitch welding the coolant conduits of a water-cooled flat plate solar collector to its absorber plate have been studied. A physical model of the heat transfer process from the plate to the fluid flowing inside the tube has been presented. The heat transfer coefficient based on the difference between bond temperature and fluid bulk mean temperature is an important factor in determining the collector efficiency factor F'. The upper and lower limits of the actual value of F' have been predicted by considering two extreme boundary conditions to which the fluid is subjected. For a thick and conductive tube wall, F' does not depend on spot size and spot spacing, and tends to an upper limit of 0.883. For a thin and non-conductive tube wall, the boundary condition comprises of a series of step changes in both the axial and circumferential directions of the heat flux. In this case, the heat transfer coefficient and hence F' approach their lower limits which are determined by the welding spot configuration. It was also found that F' increases with the following parameters: the spot angle; the percentage of tube length being welded; and the number of spots among which the welding is being distributed. Furthermore, the temperature distribution inside the fluid has also been computed for this case. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate
2

The modelling of solar radiation quantities and intensities in a two dimensional compound parabolic collector

Moodaly, Asogan 15 March 2010 (has links)
M.Ing. / A dissertation presented on the basic solar design principles such as sun-earth geometry, energy wavelengths, optics, incidence angles, parabolic collector configurations and design, materials for solar applications, efficiencies, etc to be considered in Solar Concentrating Collector design. These principles were applied in the design and fabrication of a prototype solar collector. The solar collector was tested to verify and correct mathematical models that were generated from existing literature; as well as for optimization work.

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