A self-powered PV-TEG system for integrated hotspot monitoring and local thermal management based on thermoelectric voltage response

Distributed photovoltaic (PV) systems pose challenges for localized hotspot monitoring because modules are often dispersed and difficult to access. This study develops a self-powered photovoltaic–thermoelectric generator (PV–TEG) system in which a rear-side 2 × 2 TEG array integrates hotspot sensing, local thermal management, and wireless monitoring. A multiphysics model was established to characterize the coupling among hotspot position, thermoelectric voltage response, and local cooling and to construct a two-dimensional localization mapping from four-channel voltage responses. The system was then deployed on a rooftop PV array at a telecommunications facility in Taizhou, China, for outdoor validation. Numerical results showed that different hotspot positions produced spatially differentiated TEG voltage signatures, enabling coordinate reconstruction, while the local temperature reduction ranged from 8.15 to 12.40 K. Field tests from 08:00 to 18:00 showed that harvested thermoelectric energy cycled the supercapacitor between 2.8 and 4.0 V, supporting temperature and voltage acquisition and approximately 45 wireless transmissions to a mobile terminal. Infrared measurements showed that the PV–TEG structure reduced the local point temperature and regional average temperature by 7.7 and 5.4 °C, respectively, confirming its capability to mitigate local heat accumulation. For a controlled black-tape-induced hotspot-like anomaly, coordinate reconstruction yielded a two-dimensional localization error of 9.93 mm. These results demonstrate the feasibility of extending TEGs from conventional waste-heat harvesters to distributed thermal-field sensing nodes, providing a new approach to low-power online fault monitoring in distributed PV systems.