Experimental investigation of the photovoltaic thermal integrated with ground heat exchanger using volcanic tuff stones

This study evaluates the performance of a photovoltaic thermal (PVT) system integrated with a ground heat exchanger (GHE) utilizing volcanic tuff stones as a heat storage material. In contrast to conventional PVT systems, this innovative approach leverages the thermal conductivity and porosity of volcanic tuff stones to enhance heat storage capacity and cooling efficiency. While previous research has focused on standalone PVT systems or GHE applications, limited attention has been given to their integration using natural materials. This study addresses this gap by experimentally investigating the combined system's thermal and electrical performance under real outdoor conditions in Tafila, Jordan. The experimental setup included a polycrystalline solar module coupled with a GHE designed to enhance electrical, thermal efficiencies and thermal storage. The results show that integrating the GHE reduced the Solar cell's temperature by up to 23 %, improving electrical efficiency by 4 % and increasing electrical power output by 6.56 % compared to a standalone PVT system. Thermal efficiency also improved significantly, reaching 70.60 % compared to 58.66 % thermal efficiency in the PVT system. The GHE raised outlet air temperatures by an average of 10 °C above ambient, demonstrating effective heat recovery. Furthermore, when coupled with a fan coil unit, the system reduced energy consumption by 14.81 % during the heating season. These findings highlight the novelty of integrating volcanic tuff stones into PVT-GHE systems, offering a sustainable solution for improving energy efficiency and thermal performance in renewable energy applications.