Thermal performance investigation of rhombus shape roughened solar air collector- A novel approach

Current study investigates parametric study on thermal performance of a rhombus-shaped artificially roughened absorber plate (RAP) used in solar air collector. Experimental investigations were performed in month of April–May 2024 in mechanical department of MANIT, Bhopal. Relative roughness pitch (P/e), relative roughness height (e/D_h), number of elements (W/V_r) and relative diagonal length (d_r/e) in the range of 8–12, 0.0225–0.03375, 9–11, and 8–12 respectively are used as geometrical parameters for current study. Reynolds number (Re) is varied from 2000 to 14000. Thermal efficiency (ղ_th) is reported in terms of collector heat removal factor (F_R), and collector efficiency factor (F′). A significant enhancement in ղ_th has been observed, ranging from 1.42 to 1.63 times higher when compared to the performance data of smooth plates. Maximum ղ_th of 79.48% was found at P/e = 10, e/D_h = 0.03375, W/V_r = 10, d_r/e = 9.6 at mass flow rate ($\dot{m}$) = 0.031 kg/s. Collector's performance parameter are reported as (F_Rτα) and (F₀U_L). value of (F_Rτα) and (F₀U_L) is reported 0.8612 and 15.82 for rhombus shape at optimal geometrical parameters.