Photovoltaic thermal hybrid system (PV/T) design for agricultural drying applications

Intensive use of conventional energy sources in agricultural processes increases operating costs and may cause various environmental problems in the long term. For this reason, the use of renewable energy sources such as geothermal, biomass, wind and solar in the agricultural field is becoming increasingly important. Within this thesis, it is aimed to use a photovoltaic-thermal hybrid system for grape drying. The hot air obtained by using the designed and manufactured air-cooled photovoltaic-thermal (PV/T) system was used to support drying. Drying and PV performance experiments were carried out in the years of 2021-2023. In panel performance experiments, thermal efficiency values of 38,04% in the rectangular section panel and 34,06% in the circular section panel were reached. However, the highest instantaneous thermal efficiency value of 45% was achieved in hybrid panels. Although the total amount of electrical energy produced and electrical efficiency values depending on the total energy falling on the panel surface did not differ greatly, they were found to be slightly higher in the control group. In this case, it is seen that hybrid panels provide a significant advantage over the classic control panel without any cooling mechanism in terms of total efficiency values, along with increases in thermal efficiency achieved without any significant loss in electrical output. Although the heat exchanger system with a rectangular section geometry, which is one of the heat exchanger systems with two different geometries used in panel cooling, has a disadvantage in terms of drying time, it has been determined that it absorbs more heat than the circular section and therefore has higher thermal efficiency at all measurement points. Considering the food values in general, it is determined that PV/T systems with rectangular cross-section heat exchangers can produce technically expected and predicted drying outputs and are recommended to potential manufacturers in the market.