Numerical Investigation of Solar Air Heater with New Design Offset Finned below the Absorber Plate

Conference: Fifth International Conference on Emerging Trends in Engineering & Technology
Author(s): Shalini Rai, Prabha Chand, S.P.Sharma Year: 2016
Grenze ID: 02.IETET.2016.5.5 Page: 25-30

Abstract

Energy is never destroyed during a process; it changes from one form to another (First Law of Thermodynamics). In contrast, energy accounts for the irreversibility of a process due to increase in entropy (Second Law of Thermodynamics). Energy is always destroyed when a process involves a temperature change. In this paper the thermal, thermo hydraulic and exergy efficiencies of an offset finned solar air heater have been evaluated theoretically. Parametric study was done to investigate the effect of variation of offset fin parameters i.e. fins spacing and fins height at different mass flow rates on the thermal, thermo hydraulic and energy efficiency. The results indicated that attaching offset finned below the absorber plate at low mass flow rates can lead to noticeable enhancement of exergy efficiency. Decreasing the fins height and fins spacing are effective at low mass flow rates, but at high mass flow rates the inverse trend is observable, such that energy efficiency reduces sharply. The effects of air mass flow rate ranging between 0.01388 to 0.0833 kg/s on the collector efficiency factor, heat removal factor, outlet temperature, thermal, thermo hydraulic (effective) and energy efficiency .The efficiencies of offset finned solar collector were compared with conventional flat-plate.

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IETET - 2016