Determination of the curvature derating factor for the Georgia Tech Aquatic Center photovoltaic array

The photovoltaic (PV) array on the roof of the Georgia Tech Aquatic Center (USA) is unique in that it is curved, following the curvature of the roof of the Center. This curvature leads to some power loss in the system due to the difference in irradiance over the area of the array, as well as difficulties in obtaining the system efficiency from measured data. These problems could become increasingly common as more PV arrays are integrated into building structures. This paper describes a simple method of overcoming these difficulties using a "curvature derating factor". First, the parameter is defined. Model calculations are then employed to obtain an estimate of the parameter's value for a particular system. Finally, an experimental estimation of the parameter is described, and its results are compared with the predictions.