Researchers led by scientists at Southeast University in China have developed a self-powered photovoltaic-thermoelectric generator (PV-TEG) system designed to detect hotspots in solar panels, manage local heat and transmit monitoring data wirelessly. The system uses an array of four thermoelectric generators (TEGs), which produce electricity from temperature differences and also provide signals that help locate thermal anomalies.
The researchers first modeled a 500 mm by 500 mm photovoltaic area fitted with four TEGs and an aluminum heat sink. In simulations, different hotspot positions produced distinct voltage patterns across the devices, which the team used to map anomalies to two-dimensional coordinates. Simulated local temperature reductions ranged from 8.15 K to 12.40 K.
The team also tested the system outdoors on a rooftop solar array at a telecommunications facility in Taizhou, eastern China. To assess detection accuracy, they created thermal disturbances at three locations using black tape, measured the TEG voltage responses and compared the reconstructed positions with infrared imaging.
In the outdoor tests, the system localized hotspots with an error of approximately 9.93 mm. It reduced the PV surface temperature by up to 7.7 C at the measured point, with an average reduction of 5.4 C across the monitored region.
The monitoring electronics operated without an external power supply, using a supercapacitor that triggered operation at 4.0 V and switched off at 2.8 V to recharge. Across a 10-hour daytime test, the system completed approximately 45 wireless transmissions.
The researchers say they plan to study performance under electrically induced hotspots and more complex outdoor conditions. The work, involving scientists from Southeast University and the University of Technology Sydney, was published in Applied Thermal Engineering under the title “A self-powered PV-TEG system for integrated hotspot monitoring and local thermal management based on thermoelectric voltage response.”
Sources: pv magazine.