Experimental performance investigation on the effect of step change in absorber plate thickness of flat plate solar collector

Over the years, several geometrical and operational improvements have been made to the solar flat plate collector to utilize the solar energy more effectively. The present study investigated the effect of the step-change in absorber plate thickness on the thermal performance of flat plate solar collectors (FPCs). Two configurations were developed of which one featuring a uniform absorber plate thickness of 0.4 cm and the other exhibiting a variable thickness, segmenting the plate into equal portions of 0.2 cm and 0.6 cm. Both designs were assessed under diverse solar radiation and meteorological situations to measure their heat gain, temperature increase, and efficiency. The findings indicated that the step-changed design attained an efficiency enhancement of 4.6–12.7 % compared to the uniform plate, with peak efficiency reaching 67.7 %. The thicker portion of the step-changed plate improved thermal performance by decreasing thermal resistance and maintaining heat transfer during variable radiation conditions. Nonetheless, its thermal inertia impeded heat transmission under low radiation circumstances. These findings illustrate the potential of step-changed absorber plates as a cost-efficient, enhanced thermal performance substitute for FPCs, providing significant insights for the advancement of solar thermal technology.