Determination of Effective Efficiency of Artificially Roughened Solar Air Heater Duct Using Ribs
Artificial surface roughness is used to increase the thermal performance of a solar air heater. The intent is to improve heat transfer between the absorber plate and air flowing through the duct. However, roughness also increases the force required to flow air through the duct, which leads to an increase in the pumping power required in the duct, thus resulting in a decrease in the effective or overall efficiency of the solar air heater duct. In this article effective efficiency of various geometries used in solar air heater are computed by the use of heat transfer and friction factor experimental correlations. A comparison is also presented for the selection of optimum roughness geometry.
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