Author : Mohitkumar G. Gabhane and A. B. Kanase-Patil

Solar Air Heater (SAH) provides the efficient use of solar energy, which uses absorber plate to absorb incoming solar radiation, converting it to thermal energy and transfers thermal energy to fluid flowing through it. By making SAH double pass, heat transfer rate is enhanced. The method of using Artificial Roughness (AR) on absorber plate is best option to increase heat transfer rate significantly and gives better results than any other method. For good thermohydraulic performance, double flow-double pass arrangement is used. This investigation presents correlations for double flow-double pass SAH having smooth aluminum plate as absorber. Correlations are developed for Nusselt number, Friction factor, Stanton number and Thermohydraulic efficiency. These parameters are help to know overall performance of SAH. Correlations are based on Experimental and CFD simulation data values. Reynolds number is varied from 3000 to 15000. Least square method is used to developed correlations. All correlations are validated by comparing with CFD and experimental values respectively. These correlations are found to predict the experimental results with reasonable accuracy.

Keywords: Convective heat transfer, Double pass SAH, Correlations, Smooth absorber plate, Least square method.