Effects of Damp-heat on Shunt, Series Resistances and Fill Factor into Crystalline Silicon Photovoltaic Solar Modules in Tropical Zone

Most solar module manufacturers guarantee the minimum performance of their modules for 20 to 25 years. But some time after their installation, one observes faults which appear on the various components of these modules. During long-term exposure to severe climatic conditions, these faults, which accumulate over time, lead to performance losses of the module. This performance degradation is due to several factors such as humidity, temperature, heat, irradiation etc. These factors cause various degradation processes which can be electrical, chemical, mechanical, thermal, etc. The tropical zone, the middle of our study being characterized by high heat and humidity, has definite impacts on the electrical parameters of photovoltaic modules. The electrical parameters degradation is among others cause of photovoltaic modules performance loss. This study purpose is to study the degradation of the shunt resistance, the series resistance and the form factor of photovoltaic modules installed in tropical areas in order to appreciate their impact on the performance loss of the latter. For that, we used Peck performance degradation analytical model and Braisaz degradation analytical models of shunt resistance and the series resistance to calculate over a period of forty years, in real conditions in the tropical environment, the degradation of these electrical parameters of the photovoltaic module. The results obtained are compared to those obtained during the Hulkoff experimental tests in the state of Miami in Florida in 2009. The degradation rates obtained in the six cities concerned by the study vary between 17.33-35.67% for resistance shunt, between 3.77-7.55% for the series resistance and between 8-19% for the fill factor. In addition, these electrical parameters degradation rates obtained experimentally by Hulkoff and taken up by [1], are respectively 35.14% for the shunt resistor, 9.43% for the series resistor and 3.03% for the fill factor over the study period.