<p>The drying process is a fundamental activity in the food industry that demands a definite quantum of energy and time. This analysis presents an experimental analysis of an indirect type solar dryer (ISD) without and with a thermal energy storage (TES) system (method -1 and method -2) while drying bitter gourd slices. The dryer consists of a solar air collector, a TES device, and a drying section with four equally spaced wire mesh trays. The TES device is made with paraffin wax, which releases latent and sensible heat after sunset, allowing the dryer (method-2) to work efficiently for the next seven hours. The acquired experimental data were fitted to 13 existing drying models, and the best was selected based on the comparison of the coefficient of determination (<i>R</i>^<i>2</i>) and reduced chi-square (<i>χ</i>^<i>2</i>). The drying models of the Logarithmic model were identified to be better with <i>χ</i>^<i>2</i> = 96.06658, 90.9233, 119.3623 and <i>R</i>^<i>2</i> = 0.9744, 0.975, 0.968 in method-1, method-2 and open sun drying, respectively. The activation energy was determined as 102.3 and 90.38&#xa0;kJ/mol in methods-1 and 2, respectively. A decrement of 13.18% in activation energy was noted in method-2 in comparison to method-1. A 23.24% and 41.33% decrement in the average diffusion coefficient and specific energy consumption and a 70.44% increment in specific moisture extraction rate are noticed in method-2 compared with method-1. Addition of TES system saved the drying time of 1&#xa0;day hence it needs to be added in all conventional and commercial solar dryers.</p>