Energy and Exergy Investigation of a Solar Air Heater for Different Absorber Plate Configurations

Abstract

This study examined the effects of various absorber plate designs, such as one line finned 
flat absorber and two lines finned absorber plate, on the thermal performance of a flat plate double 
passing solar air heater. In order to increase thermal efficiency, L-shaped fins are soldered onto the 
absorber plate to roughen it and create vortices that facilitate heat transmission between the absorber 
plate and the working fluid (air). The meteorological conditions of Baghdad city (longitude 33.3 N and 
latitude 44.44 E) were used for the outdoor experimental test between February and May. According to 
the findings, the air temperature for a single line of fins is 48 °C, 47.5 °C, and 58.5 °C at an air 
velocity of 1.7 m/s; for two lines of fins, it is 52 °C, 57.5 °C, and 66 °C at an air velocity of 0.9 m/s. At 
an air velocity of 0.9 m/s, the efficiency increases by 28% for one line of fins and 66% for two lines of 
fins; at an air velocity of 1.7 m/s, the efficiency increases by 27% and 51%, respectively. When the 
velocity rises from 0.9 m/s to 1.9 m/s, the average exergy destruction rate increases by 37.6%, 60.6%, 
and 68.66% for the absorber plate, working fluid, and glass cover, respectively. When the velocity 
increased from 0.9 m/s to 1.9 m/s, the exergy efficiency rose by 24.1%.