Comparative Thermo-Electrical Performance of Monocrystalline and Polycrystalline Silicon Photovoltaic Modules Under Extreme Temperatures

Operating temperature is a critical factor limiting the performance and reliability of photovoltaic (PV) systems, particularly in Sahelian regions where modules are exposed to substantial thermal fluctuations. Although temperature effects on PV performance have been widely investigated, experimental evidence remains limited on the comparative thermo-electrical response of monocrystalline and polycrystalline silicon modules under a broad range of extreme temperatures while simultaneously considering electrical characteristics, effective temperature coefficients, and thermal dynamics. This study addresses this gap through a controlled experimental comparison of both technologies over a temperature range of 5–70°C at a constant irradiance of approximately 450 W.m -2 , representative of moderate solar operating conditions. A solar simulator coupled with a PV150 photovoltaic analyzer was used to systematically characterize the current–voltage (I–V) and power–voltage (P–V) characteristics, energy conversion efficiency, effective maximum power temperature coefficients, and heating and cooling dynamics of the two PV technologies. The results demonstrate a consistent temperature-dependent degradation of electrical performance: increasing temperature slightly increases short-circuit current, whereas open-circuit voltage, maximum power output, and conversion efficiency progressively decline. Between 30°C and 70°C, the efficiency of the monocrystalline module decreased by 11.92%, compared with only 6.68% for the polycrystalline module, while cooling to 5°C increased efficiency by 8.52% and 14.57%, respectively. The experimentally determined maximum power temperature coefficients were −0.30%.°C -1 for the monocrystalline module and −0.17%.°C -1 for the polycrystalline module, revealing a markedly lower thermal sensitivity and greater thermal stability of the polycrystalline technology under the investigated conditions. Beyond quantifying conventional temperature-induced losses, the originality of this study lies in the integrated experimental assessment of electrical degradation, effective thermal sensitivity, and transient thermal behavior across an extended temperature range under controlled irradiance, providing experimentally derived evidence relevant to harsh Sahelian environments. These findings have direct practical implications for PV technology selection, performance prediction, thermal derating, and the design of thermal management strategies, particularly for installations exposed to severe heat stress. The results also provide experimental benchmarks for improving temperature-dependent PV performance models and supporting the development of climate-adapted operation and maintenance strategies for high-temperature photovoltaic systems.