Investigation of heat transfer and friction characteristics of packed bed solar air heater using wire mesh as packing material

An experimental investigation has been carried out on a packed bed solar air heater using wire mesh as packing material. Data pertaining to heat transfer and friction characteristics were collected for air flow rates ranging from 0.0159 to 0.0347 kg/s-m² for eight sets of matrices with varying geometrical parameters. The thermal efficiency of a packed bed solar air heater was compared with that of a conventional solar air heater to determine the enhancement which was found to be strong function of system and operating parameters of the bed. It was found that an enhancement of the order of 76.9-89.5% can be obtained. Experimental data were utilised to develop correlations for Colburn J_h factor and friction factor as function of geometrical parameters of the bed and the flow Reynolds number. These correlations were found to predict the experimental results with reasonable accuracy. It has also been found that the present correlations show much better agreement as compared to the values predicted by earlier correlations for such systems.