Exergetic efficiency analysis of impingement jets integrated with internal conical ring roughened solar heat collector

In the present work, the exergetic efficiency $\left({\eta }_{\mathrm{e}\mathrm{x}\mathrm{g}}\right)$ of a solar heat collector with air jet impingement on an internal conical ring-roughened absorber plate has been analytically determined. The motivation behind the present investigation is to determine the performance of the selected heat transfer enhancement technique in order to bring out the feasibility of the investigation. The geometric parameters of the absorber plate and the jet plate that have been examined are derived from the internal conical ring height $({\mathrm{H}}_{\mathrm{R}})$, inlet flow diameter $({\mathrm{D}}_{\mathrm{I}\mathrm{R}})$, internal print diameter of ring $({\mathrm{D}}_{\mathrm{B}\mathrm{R}})$, streamwise pitch $({\mathrm{X}}_{\mathrm{S}})$, and spanwise pitch $({\mathrm{Y}}_{\mathrm{S}})$. The optimum values of the roughness parameters have been determined. The optimal values of geometric parameters that fetch the highest ${\eta }_{\mathrm{e}\mathrm{x}\mathrm{g}}$ for $Re$ in the analyzed range between 4000 and 12,900 are a relative roughness height of ${\mathrm{H}}_{\mathrm{R}}/{\mathrm{D}}_{\mathrm{H}}=0.110$, a ratio of internal flow diameter to internal print diameter of ring of ${\mathrm{D}}_{\mathrm{I}\mathrm{R}}/{\mathrm{D}}_{\mathrm{B}\mathrm{R}}=1.7$, a ratio of ring diameter to ring height of ${\mathrm{D}}_{\mathrm{O}}/{\mathrm{H}}_{\mathrm{R}}=2.33$, a relative streamwise pitch of ${\mathrm{X}}_{\mathrm{S}}/{\mathrm{D}}_{\mathrm{O}}=5.28$, and a relative spanwise pitch of ${\mathrm{Y}}_{\mathrm{S}}/{\mathrm{D}}_{\mathrm{O}}=3.42$. As compared with smooth duct, the ${\eta }_{\mathrm{e}\mathrm{x}\mathrm{g}}$ value of the solar heat collector investigated was found to be enhanced 2.2 times higher under similar analytical conditions.