Energy and exergy analysis of a trapezoidal absorber plate-based solar air collector

This study presents energy and exergy characteristics of solar air collectors (SACs) having two different absorber plates, namely flat (Model-I) and trapezoidal (Model-II) plates. Experiments were conducted at different tilt angles of 15o, 30o, and 45o and varying mass flow rates (MFR) from 0.0039 kg/s to 0.0156 kg/s in an open environment. Results indicated that with an increment in MFR, the outlet temperature decreases while the heat extraction rate improves. Quantitatively, increasing MFR threefold improves thermal efficiency by 60% and reduces exergy efficiency by 39%. Furthermore, its efficiency increased by 38%-66% when the inclination angle is increased from 15o to 45o. The energy and exergy efficiencies of Model-II were increased by 8.5% and 8.4%, respectively, more than that of Model-I. Results indicated that the trapezoidal plate-based collector offers better heat extraction characteristics and performs better in terms of energy, exergy, effective efficiency, and temperature rise than its flat counterpart.