Factors affecting module performance

 Factors affecting module performance:- 

The performance of a module under the real-life (outdoor) conditions depends on the PV technology employed and the environmental conditions of the location. The irradiance and ambient temperature are two main factors that affect the performance of PV modules. It can be observed that short circuit current is directly proportional to the irradiance, i.e. it increases as irradiance values are increased. This is brought about by the rise in the number of photons to activate the electrons from the valence band of the photo-voltaic structure to the conduction band, hence producing more current. The irradiance level is increased from 0.1 kW/𝑚2 to 1 kW/𝑚2 in steps of 0.1. It is also established in the literature that the VOC decreases substantially when the temperature increases, compared to short circuit current which only slightly increase with temperature. This is going to be investigated in the performance analysis simulation. It is noteworthy that the cell or module temperature is always higher than the ambient temperature, i.e., the implication of this is that the band gap of the solar cells in the module is lowered. Therefore, the overall power output of the module reduces, and because of the power/efficiency correlation, the module efficiency also reduces. For crystalline PV cells, VOC decreases by around 0.37% per degree Celsius rise in temperature but ISC increases by about 0.05% under the same condition .when PV cells heat up, the maximum power point shifts away toward the left with a drop in maximum power output, by about 0.5% per degree Celsius temperature rise. The temperature dependence of VOC.