Thermo-Economic evaluation of a solar dryer with evacuated heat pipe collector and energy storage

In this experimental study the effect of using phase change materials (PCM) in the thermal storage tank on the performance of a solar dryer was investigated. The experiments were carried out for three levels of PCM 1.54, 2.45 and 3.6 kg and two levels of fluid flow rate of 0.2 and 0.4 l/min. The results showed that with increasing the fluid flow, the thermal efficiency of the collector from 62.4% to 20.2% for 0.4 l/min. The thermal energy for fluid flow of 0.2 and 0.4 lit/min obtained about 13.31 to 13.63 MJ and 14.45 to 14.92 MJ, respectively. The results also showed that the overall efficiency of the dryer increased with increasing PCM and it changes from 32.92% to 35.55% for the fluid flow rate of 0.2 l/min and 32.19% to 36.02% for 0.4 l/min. Considering the specific energy used for drying of the samples and drying efficiency the fluid flow with 0.2 l/min and PCM with 3.6 kg is a proper choice for drying of apple slices. The payback period was obtained about 20 months.