Determining the effect of inlet flow conditions on the thermal efficiency of a flat plate solar collector

The main objective of this study was to investigate the effect of inlet temperature (Tin) and flowrate ( m˙ ) on thermal efficiency (ηth) of flat plate collectors (FPC). Computational Fluid Dynamics (CFD) was employed to simulate a FPC and the results were validated with experimental data from literature. The FPC was examined for high and low level flowrates and for inlet temperatures which varied from 298 to 373 K. Thermal efficiency of 93% and 65% was achieved at 298 K and 370 K inlet temperature’s respectively. A maximum temperature increase of 62 K in the inlet temperature was achieved at a flowrate of 5 × 10−4 kg/s inside the riser pipe. Tin and m˙ were optimised in order to achieve the minimum required feed temperature for a 10 kW absorption chiller.