Abstract
The present paper describes the experimental analysis of heat transfer and friction factor for glass protected three-side artificially roughened rectangular duct solar air heaters (SAHs) having an arrangement of multiple-v and transverse wires (top wall multi-v and two side walls transverse) under the absorber plate, and compares their performance with that of one-side roughened solar air heaters under similar operating conditions. The investigated three-side solar air heaters are characterized by a larger rate of heat transfer and friction factor as compared to one-side artificially roughened SAHs by 24–76% and 4–36%, respectively, for the identical operating parameters. The air temperature below the three-side rugged duct is by 34.6% higher than that of the one-side roughened duct. Three-side solar air heaters are superior as compared to one-side artificially roughened solar air heaters qualitatively and quantitatively both.
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