Enhancing Photovoltaic-Thermoelectric Generator (PV-TEG) system performance via mathematical modeling and advanced thermal interface material: An emphasis on Pyrolytic graphite Sheet (PGS)

•Improving PV-TEG efficiency by tackling metal surface and air gap thermal challenges.•Proposing mathematical modeling for predictive performance evaluation of PV-TEG systems.•Investigating the effectiveness of PGS as a TIM in PV-TEG systems.•Assessment of three cooling approaches: natural air, forced air, and forced water.•Bent PGS configuration proves most effective in reducing PV panel temperature to enhance power generation. PV-TEG systems utilize waste heat by using TEGs under PV panels. TEGs improve the efficiency of PV and generates more energy. However, rough metal surfaces at contact points reduce the system's thermal efficiency and create air gaps. This paper employs a mathematical model based on principles of thermal resistances and energy conservation. The proposed model is built using MATLAB R2020a. The paper assessed the effectiveness of a Pyrolytic Graphite Sheet (PGS) as a Thermal Interface Material (TIM) in PV-TEG systems and three cooling approaches. The investigation explores two configurations (parallel and bent) of PGS and five TIM materials. The results indicate that bent PGS is the most effective. It lowers the temperature of the PV panels to 18.99 ℃, 19.95 ℃, and 20.74 ℃. As a result, the power increased to 0.606 W, 0.639 W, and 0.667 W. Additionally, the efficiency improves to 1.66 %, 1.75 %, and 1.82 % with natural air, forced air, and forced water cooling, respectively. The results show that PGS can improve PV-TEG system performance and solve thermal issues with metal surfaces and air gaps.