Numerical model of natural convective heat transfer within a solar dryer using an indirect double pass collector

The double pass collector is one of the most efficient means of drying crops because heating of air takes place from both sides of the absorber plate. To investigate the performance, a double pass natural convection solar dryer was fabricated for experimentation; the results were collected and used to develop a validated numerical model using MATLAB. The experiments were undertaken during February–March 2016 in Salem Tamil Nadu, India over 10 sunshine days. The simulation was carried using the developed model under the measured ambient conditions. The results showed that the mathematical model could predict the performance of the double pass collector for a particular ambient condition to an uncertainty of ±5%. This model could be used to optimise the performance of the collector so that we can predict and investigate the actual performance of the collector with the various optimised designs before fabricating the dryer.