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Influence of shadow on shunt-type potential-induced degradation for crystalline Si photovoltaic modules exposed outdoors
摘要： Potential-induced degradation (PID) was observed for crystalline Si photovoltaic (PV) modules set at a PID test system constructed outdoors. It was clearly shown that partial shadow and periodical water spray during daytime accelerate PID generation. PID easily occurred just underneath the shielding plate. It was also found that when a large part of one cell in the PV module was shadowed, PID is accelerated; however, when a small part of one cell in the PV module was shadowed or when the weak light is uniformly irradiated, less PID acceleration is observed. Simulation was also carried out for discussing the influence of light irradiation. These findings suggest that UV irradiation during the PID indoor test is essential for the exact estimation of the acceleration factor of the indoor PID test.
关键词： shadow,outdoor test,UV irradiation,potential-induced degradation,crystalline Si photovoltaic modules
更新于2025-09-23 15:19:57
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Experimental Investigation of the Shading and Mismatch Effects on the Performance of Bifacial Photovoltaic Modules
摘要： Bifacial photovoltaic (PV) modules are drawing increasing attention because of their potential in gaining extra energy from the rear-side irradiance. However, the rear-side irradiance can cause the performance of bifacial PV modules to be different from the performance of monofacial PV modules under shading and mismatch conditions. For bifacial modules, two factors can lead to the irradiance mismatch: the front-side partial shading and the rear-side irradiance inhomogeneity. This experimental work aimed to study the impact of these two factors on the performance of bifacial PV modules. The effect of front-side partial shading was investigated by comparing the electrical and thermal behavior of bifacial and monofacial PV modules under different shading conditions. The influence of rear-side irradiance inhomogeneity was investigated by analyzing the operating voltages of the solar cells in a bifacial PV module under certain typical installation conditions. To further explain the origin of the mismatch effect, a diode model circuit was applied in the analysis. The results indicate that even when the bypass diode of the bifacial PV module was activated, the shaded bifacial cells still received extra irradiance and produced higher heat. Thus, in most cases, the mismatch caused by the front-side partial shading may result in a greater reliability risk for the bifacial PV modules compared with the monofacial PV modules. For the mismatch effect of bifacial PV modules caused by the rear-side irradiance inhomogeneity, the significant reliability issues (such as reverse bias of solar cells and hotspot problems) would rarely happen, mainly because of the limited inhomogeneity of the equivalent irradiance and logarithmical increasing relationship between the voltage deviation and irradiance deviation of each solar cell.
关键词： shading effect,mismatch,thermal characteristic,Bifacial,outdoor test,photovoltaic (PV) module
更新于2025-09-12 10:27:22
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Performance evaluation and degradation assessment of crystalline silicon based photovoltaic rooftop technologies under outdoor conditions
摘要： Keeping track of ?eld performance and degradation rate of photovoltaic panels in regions with diverse environmental exposures is critical. The objective of this paper is to determine two and half year performance characteristics and degradation rate of poly-crystalline and heterojunction with intrinsic thin layer roof-top photovoltaic units under prevailing weather conditions in the Central Anatolia region. Degradation rates of the photovoltaic units were determined through analysing the effective peak power, and the temperature corrected performance ratio of each technology. Processing of the measured data covering the test period reveals that the thin ?lm technology offers lower degradation rate with nearly (cid:1)0.1% than the poly-crystalline based technology within the range of (cid:1)0.67% to (cid:1)0.83%, respectively. The study allows a better understanding of variations in performance and behaviour of the output power of poly-crystalline and heterojunction with intrinsic thin layer roof-top photovoltaic units after 2.5 years of outdoor exposure.
关键词： Degradation rate,Performance,Outdoor test,PV
更新于2025-09-11 14:15:04