4E: Energy, effective, exergy and economic based performance investigation for rectangular pyramid shaped roughened solar collectors

The present experimental investigation is aimed at determining 4E: Energy, Effective, exergy and economic based performance investigation for rectangular pyramid shaped roughened solar absorbers. The investigation was conducted outdoors at the rooftop of mechanical engineering department, MANIT Bhopal during February to June 2023. Data for air and absorber’s temperatures were measured at different locations using k-type thermocouples. Roughness in form of rectangular pyramid was imparted on flow side of absorber. Rise in heat transfer for rough plates compared to smooth were more than that of heat transfer obtained for rhombus and sinusoidal roughness. Roughness geometric parameters were varied and tested to determine Nusselt number, friction factor and THPP. Investigation covered relative rectangular pyramid height ( e / D h ), relative rectangular pyramid pitch ( p / e ), relative base length to width ratio ( b L / b W ), roughness height to base length ratio ( e / b L ) and Reynolds number (Re) varied respectively as 0.033–0.054, 8–20, 1.25–2, 0.35–0.63 and 3350–13350. The outcome of paper focusses on determination of maximum rise in friction and Nusselt number for varying p / e , e / D h , e / b L and b L / b W . Rise in friction and heat transfer for the proposed roughness system lie in range of 4.66–5.6 and 4.58–6.09 times respectively. The maximum effective efficiency achieved was 76.5%, maximum exergy efficiency reached 33.4% under optimized conditions and thermohydraulic performance was found to be as 3.9, 3.8, 4.1 and 4.0 at p / e = 16, e / D h = 0.054, e / b L = 0.58 and b L / b W = 2, respectively.