A Numerical Investigation into the Thermohydraulic Performance of a Spiral Triangle Solar Air Heater

Abstract

In the present study, the thermohydraulic performance of the solar air heater with a triangular absorber plate is numerically investigated. Five various configurations of the absorber plate depend on the number of passageways that were conducted to find the optimum number of passageways. The mass flow rate was chosen between 0.0078 kg/s and 0.0758 kg/s, with an interval of 0.0068 kg/s. The surface area of the collector and bed height were 1 m² and 0.08 m, respectively. The distances between the passageways were chosen as 0.21 m, 0.15 m, 0.11 m, 0.084 m, and 0.073 m, respectively, at two, three, four, five, and six passageways. The numerical analysis was carried out using the ANSYS-FLUENT 2024 R2 solver. The highest effective efficiency, thermal efficiency, and outlet temperature were calculated under different operating conditions. The maximum effective efficiency of 75.4% was achieved at a middle of the range of passageway and mass flow rate, respectively, of three and 0.0418 kg/s. The thermal efficiency reached a peak value of 94.2% at the highest mass flow rate of 0.0758 kg/s with five passageways, however, the effective efficiency reduced to 0% because of the significant growth in pressure drop. Therefore, for arrangements with more than four passageways, mass flow rates beyond 0.0350 kg/s are not suggested.

Keywords

• Air passageways
• CFD
• Effective efficiency
• Solar air heater
• Thermal efficiency

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