Experimental energy and exergy analysis of a flat plate solar air heater with a new design of integrated sensible heat storage

Abstract

This paper presents an experimental energy and exergy analysis of a novel flat plate solar air heater (SAH). It has a specially designed absorber plate made up of copper strips (copper tubes with extended copper fins on both sides), welded longitudinal to one another. This structure acts as an integrated absorber-cum-storage unit, where a high quality synthetic oil (Therminol-55) is filled within those copper tubes as a sensible heat storage (SHS) medium. To study the impact of this novel design and the sensible heat storage over the performance of the SAH, the results were compared with the output of a conventional SAH of similar dimensions. For the precise comparison of their performances, the experiments were conducted on both the SAHs at same location, simultaneously. It ensures identical testing conditions such as the amount of solar radiation received and surrounding environment of the experimental setup. Exergy analysis is a powerful thermodynamic tool and it helps in computing the actual output of a system, theoretically. It helps the researchers to optimize the system design to compensate the present and also the future needs. Experiments were conducted for two different mass flow rates (0.018 kg/s, and 0.026 kg/s). The results showed that the maximum energy and exergy efficiency obtained was in the range of 49.4–59.2% and 18.25–37.53% respectively, for the SAH with sensible storage at m˙ = 0.026 kg/s. Besides, the SAH with sensible heat storage was observed to perform better than the conventional flat plate SAH without storage.