PV CHARACTERISTICS BASED ON ITS PARAMETERS

The increase in cell temperature decrease in electrical power yield and efficiency of the module are some of the common problems. That is referred as short term losses. If loss is for long term than the performance of the cell is degraded. It is dependent on environment factors like temperature, water ingress and ultraviolet intensity. The permanent structural damage caused by the development of thermal stress due to excessive heating of PV module at elevated operating temperature is known as thermal degradation of the module.

Life time and reliability are also adversely affected due to hostile weather condition, particularly high temperature. Roof top PV performance is degraded by the outside parameter like solar irradiance, ambient temperature, module temperature, dust accumulation and many more thus analyzing those effect and framing into the math model will give the solution about how to control and minimize those parameter so that performance can be evaluated to the maximum. The responsible parameter can be put into the mathematical model and analyze the effects



The tilt and azimuth angles of the array are important factors in performance and the optimal configuration depends primarily on the site latitude and the seasonal energy performance desired from the system. However in most cases the orientation and slope of the roof limit the options for

the installer. For most location in U.S there is little difference in annual solar radiation received on south facing surface tilted +/- 15 degrees from latitude. Although there are variations in amount received in certain season the lower tilt surfaces receive more insulation
in summer month the greater tilt surface receive more in winter. While west facing arrays produce less energy than south facing arrays they can help offset demand for afternoon peaking utilities.
One of the most important issue in the design of PV arrays on buildings is the structural attachment. One basic principle is to ensure that the lines and location of the array are consistent with the building features. Unless there is the potential for significant gains in performance due to orientation and shading issues, arrays should be mounted parallel to the roof surface, and centered and square with respect to the rooflines and edges. Where reflection issues are a concern, the designer must evaluate solar incidence angles to determine the angle of reflection for the given applications at all times of the day and throughout the year.


The routing of conduits or conductors from the array to the power processing components should also be as Stream lined as possible, especially where it transitions through the roof or eave of the building.The electrical efficiency of the system decreases rapidly as the PV temperature increases. Therefore in order to achieve higher electrical efficiency, the PV module should be cooled by removing the heat in some way.
In this topic the performance evaluation of PV roof top system and the factors which affects the performance of PV roof top system the critical parameters which is responsible for deciding the performance like solar irradiance, module temperature, ambient temperature, dust accumulation tilt angle and its orientation all these factors are equally responsible for performance and their net power output yield or final yield thus evaluating those performance factors analysis can be done and thus by using mathematical model the resultant output can be obtained using multiple linear regression method .