A research team led by scientists at China’s Southeast University has developed a self-powered photovoltaic-thermoelectric generator (PV-TEG) system that integrates hotspot detection, local thermal management, and wireless monitoring into a TEG array.
Thermoelectric generators (TEGs) convert heat into electricity through the Seebeck effect, which occurs when a temperature difference between two dissimilar semiconductors generates a voltage. TEGs are commonly used in industrial applications to recover waste heat and convert it into electricity. However, their high costs and limited efficiency have so far restricted their wider adoption.
In PV-TEG systems, PV panels generate electricity during the day, while TEGs harness temperature differences to produce additional electricity.
“The key innovation of our research is that we go beyond the conventional role of TEGs as waste-heat harvesters,” corresponding author Jingming Cai told pv magazine. “We demonstrate that the electrical signals generated by these devices can also reveal where thermal anomalies occur within a PV module.”
Cai said that by integrating four TEGs into a compact array, the researchers developed a system that combines hotspot localization, passive thermal management, energy harvesting, and wireless monitoring. “Essentially, we are turning the waste heat of solar panels into a source of both energy and diagnostic information,” he said.
The researchers first developed a three-dimensional multiphysics model of a 500 mm × 500 mm PV region equipped with four rear-mounted TEGs and an aluminum heat sink. The model coupled heat transfer and thermoelectric conversion under baseline conditions of 1,000 W/m2 irradiance and an ambient temperature of 25 C.
The team placed a 20 mm × 20 mm heat source at nine positions and mapped normalized TEG voltage changes to hotspot coordinates. It then evaluated localization accuracy at three additional positions, compared cooling performance with that of a bare PV module, and assessed sensitivity to environmental conditions and thermal contact resistance.
“Multiphysics simulations clarified the coupling among hotspot position, thermoelectric voltage response, and local cooling,” the researchers said. “Distinct hotspot locations generated differentiated four-channel voltage patterns, enabling quantitative mapping from normalized voltage responses to two-dimensional coordinates. The simulated local temperature reduction ranged from 8.15 K to 12.40 K.”
The researchers then conducted outdoor tests in Taizhou, eastern China, installing the PV-TEG system on a rooftop array at a telecommunications facility. They monitored TEG temperatures, supercapacitor voltage, and wireless transmission events from approximately 8 a.m. to 6 p.m. The monitoring electronics activated when the capacitor voltage reached 4.0 V and switched off at 2.8 V to allow recharging.
The team used infrared imaging to compare local point temperatures and regional average temperatures with those of a reference PV region. To evaluate hotspot localization, the researchers applied black tape at three positions to create controlled thermal disturbances, measured the voltage responses of the four TEGs, and reconstructed the anomaly coordinates. They tested each position three times, using infrared imaging to verify the location and temperature of each anomaly.
“What surprised us most was how accurately a small array of just four thermoelectric generators could identify the location of a thermal anomaly,” Cai said. “In our outdoor experiment, we achieved a localization error of approximately 9.93 mm. Meanwhile, the integrated system reduced the local 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.”
Cai said another encouraging result was that the system could operate without an external power supply for the monitoring electronics, completing approximately 45 wireless transmissions during a 10-hour daytime field test. “These findings suggest that even relatively small amounts of photovoltaic waste heat can be valuable when converted into sensing capabilities rather than simply additional electricity,” he said.
Cai said the team now plans to investigate how the system performs under electrically induced PV hotspots and more complex outdoor operating conditions. “Our long-term vision is to make solar panels capable of monitoring their own thermal health, identifying potential faults at an early stage, and reducing the need for energy-intensive monitoring infrastructure,” he concluded.
The researchers described the system in “A self-powered PV-TEG system for integrated hotspot monitoring and local thermal management based on thermoelectric voltage response,” which was recently published in Applied Thermal Engineering. Scientists from China’s Southeast University and Australia’s University of Technology Sydney contributed to the study.
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