Design optimization of photovoltaic solar fields-insight and methodology

An optimal design of a photovoltaics solar field may be formulated as an objective function with a set of constraints. The problem variables include field and collector parameters. The objective functions may meet energy or economic criteria, and the constraints are bounding conditions imposed on the design parameters. Mutual shading and masking between collector rows; effect of module temperature; and power loss of the conducting cables are taken into account. "Sizing" of PV systems is referred to the selection of a combination of PV modules and inverters. For this purpose, a wide variety of software tools are available to facilitate the design of PV systems. Sizing of PV systems using these software tools is, generally, not a general optimization procedure and improved designs (energy or economic wise) may be obtained by combining the "sizing" with optimization methods. The design parameters of a PV system includes field length and width; distance between collector rows; number of collector rows; collector width; collector inclination angle; number of modules connected in series in a string; and number of strings connected in parallel. In this article, the optimization of photovoltaic fields was formulated and applied on four objective functions: maximum annual incident energy; minimum field area; minimum plant cost; and minimum cost of unit energy. A distinction is made in this article between a theoretical and a practical optimization of a solar photovoltaic field. A theoretical optimization is based on the collector and field parameters whereas a practical optimization field is based on the characteristic data of the PV modules and inverters, in addition to the collector and field parameters. A theoretical optimization shows the tendency of the design parameter values in an optimal solar photovoltaic filed. The methodology of the present article provides an insight to optimal designs of solar photovoltaic fields.