Comparison of thermal performances of flat plate and evacuated tube solar air collector at different flow rates: experimental analysis

Abstract

The thermal performances of an evacuated tube solar air collector and flat plate solar air collector are experimentally investigated at different flow rates of air. The evacuated tube solar air collector has 40 evacuated tubes and surface area, 4.44 m2. This setup consists of a header of square shape. The header has a circular pipe at the centre through which the air flows. The setup contains fluid which works as a heat collecting medium that collects the solar heat which falls on the tubes. This heat is transferred to the air which flows through the circular pipe. The flat plate solar air collector has surface area, 1.21 m2. The absorber plate divides the collector into upper and lower sections to minimise the overall heat loss. The obtained results show that evacuated tube solar air collector has better thermal performance than flat-plate solar collector at different flow rates.