Experimental study of a novel photovoltaic-thermal-thermoelectric generator-based solar dryer for grapes drying

In the present work, a novel photovoltaic-thermal-thermoelectric generator (PVT-TEG) based solar dryer has been developed, and its drying performance is experimentally investigated and compared with open sun drying (OSD). The reason for incorporating the PVT-TEG system in the solar dryer is to improve the system's utility in practical drying applications by augmenting electrical power generation with the combination of PV and TEG along with extracting thermal energy for drying, thereby improving the overall system efficiency. Grapes drying has been performed to analyze the drying process and thermal and electrical performance of the system. The moisture content level after the experiment is evaluated as 1.71 (d.b.) from an initial value of 4.00 (d.b.) in PVT-TEG solar drying compared with 2.51 (d.b.) in OSD. The findings of the drying performance are determined as 17.81% for drying efficiency, 1.10 kWh/kg for specific energy consumption, and 0.68 kg/kWh for specific moisture extraction rate. The energy efficiencies obtained for the experiment are PV panel efficiency of 14.07%, TEG efficiency of 11.64%, PVT efficiency of 72.36%, and thermal efficiency of 48.50%. When compared to the open literature, the utility of the present novel dryer is found in terms of its enhanced drying and energy performances.