Experimental and numerical investigation of thermal performance in solar air heater with conical surface
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Date
2021
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Abstract
The absorber plate surface modifications of a solar air heater (SAH) increase the convective heat transfer rate of the inlet air. Forced convection heat transfer of air in a SAH with a staggered arrangement of conical obstacles has been carried out experimentally and numerically at mass flow rates (0.04, 0.08, and 0.1 kg/s) under ambient conditions for the aim of to enhance the thermal efficiency and to create proper volume for heat storage material in terms of the effectiveness of the SAH. The thermal efficiency for the absorber with conical obstacles was 14.0, 14.6, and 11.8% higher than the flat absorber plate for the mass flow rates, respectively. The results show that the number of Nusselt obtained in conical surface experiments was highest for all cases tested regardless of Reynolds number. The experimental results are compared with the numerical results obtained by the CFD method. The model results indicate good agreement with the experimental results. Also, the results show that the heat transfer in front of the conical elements is high, and the back is low; in the smooth absorber, a linear velocity distribution is seen along the channel; however, in the conical surface absorber, the velocity distribution due to turbulence is very variable. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
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Air preheaters , Computational fluid dynamics , Efficiency , Heat storage , Heating equipment , Mass transfer , Numerical methods , Reynolds number , Solar equipment , Solar heating , Velocity distribution , Ambient conditions , Convective heat transfer rates , Numerical investigations , Numerical results , Solar air heater , Staggered arrangement , Thermal efficiency , Thermal Performance , Heat convection