1. A computer-implemented method for designing a photovoltaic (PV) system, the method implemented by a design automation computer system in communication with a memory, the method comprising: receiving a set of site data, wherein the site data includes a set of location identifiers; determining a set of location design characteristics based on the set of site data; retrieving a set of structural product rules; identifying a subset of structural product rules associated with the set of location design characteristics; receiving a system type selection; receiving a plurality of system component selections; receiving a plurality of PV layout preferences; determining, at the design automation computer system, a PV module layout by iteratively applying a first layout algorithm to the set of site data and the plurality of PV layout preferences, the PV module layout defining a placement of a plurality of PV modules of a PV system; determining a structural layout, an electrical design, and an electrical layout based on the PV module layout; refining the structural layout based on the subset of structural product rules; determining a bill of materials based on the PV module layout, the structural layout, and the electrical layout; defining a PV system model using the structural layout, the electrical design, the electrical layout, the PV module layout, and the bill of materials; and displaying at least a portion of the PV system model on a visual display.