Abstract
Photovoltaic (PV) modules typically convert only 15-22% of incident solar energy into electricity, with commercial modules averaging around 18-20% efficiency. Consequently, approximately 80-85% of solar energy is lost primarily as heat, increasing module temperatures to 50-75 °C and reducing electrical efficiency by about 0.4-0.5% per °C above standard conditions (25 °C). This substantial thermal loss presents an opportunity for energy recovery. Integrating thermoelectric generators (TEGs) with PV modules offers an effective method to recover this waste heat and convert it into additional electrical energy. This study presents a comparative assessment of a hybrid PV-TE system's performance across three geographically diverse cities-Stockholm, Berlin, and Istanbul. The analysis is based on a hybrid experimental-numerical framework, anchored by field-based experimental data from Istanbul and extended via a validated performance model to simulate outcomes for Berlin and Stockholm. Seven commercial TEG modules were benchmarked under a standardized portable rig; among these, TEG3 and TEG4 exhibited the strongest performance enhancements across the tested conditions, with the most significant gains observed under active cooling. All performance metrics are derived from on-site measurements of solar irradiance and temperature at all three locations; external NREL/JRC datasets were consulted solely for consistency checks. The incorporation of TEGs into PV modules led to significant performance enhancements at all three test sites. Across the three locations, the hybrid configuration achieved ~ 2-5% gains with TEG3 and ~ 5-9% with TEG4, relative to a PV-only baseline under matched conditions, with the magnitude of improvement depending on local thermal conditions. Within the tested summer midday window (June-August, 11:00-15:00 local time), Berlin exhibited higher mean hybrid efficiency than Istanbul, underscoring the role of geographic and thermal context. These results highlight the strong commercialization potential of PV-TE hybrid systems and support the strategic deployment of PV-TE technology in diverse climates by leveraging site-specific thermal management.