Effect of geometrical aspects on the performance of jet plate solar air heater

The present work deals with the experimental study of effects of flow and channel spacings, Z(1) and Z(2) on the performance of a cross-flow staggered hole jet plate solar air heater. This work is carried out with mass flow rate, (m) over dot(1) = 0.030-0.065 kg/s, (m) over dot(2) = 0.020-0.043 kg/s, Reynolds number, Re = 2700-6900, depth ratio, Z(2)/Z(1) = 0.75-1.0, total air depth, Z = 0.14 m, jet hole diameter, D = 0.006 m, Number of jet holes, N = 1173 and tilt angle, theta = 22.6 degrees, The experiment is performed during the month of November December, 2013 at ISM Dhanbad, India between 9.00 AM to 3.00 PM on hourly basis in the clear sky with the help of precision instruments fitted with the setup for recording the temperature, velocity and intensity of radiation. The performance in terms of outlet temperature, collector efficiency and Nusselt no. of this solar air heater are found substantially higher at higher spacing between the jet and absorber plate (Z(2) = 0.07 m) while mass flow rate adversely affects the outlet temperature. In the present study, the non conventional jet plate solar air heater is also compared with conventional parallel plate solar air heater and it is observed that the performance of the jet plate solar air heater is always higher than conventional solar air heater. Friction factor is not significantly changed with Z(2). Based on the experimental data, the correlations for Nusselt number and friction factor have been developed. (C) 2016 Elsevier Ltd. All rights reserved.