A method to calculate array spacing and potential system size of photovoltaic arrays in the urban environment using vector analysis

The standard mathematical approach used to calculate photovoltaic (PV) array spacing contains a number of assumptions that limits its use to PV arrays installed on horizontal surfaces. This paper utilises vector analysis to develop a new method to calculate array spacing and potential system size for any combination of PV array and surface tilt and orientation. This approach is validated by comparing the vector results with ray-tracing shadow visualisations utilising the Ecotect software package. The vector method is presented as an approach compatible with online solar/PV mapping tools after a review of the existing online tools indicated that rack mounted array functionalities were rarely included. The methodology is further demonstrated via results from the Australian PV Institute's (APVI's) Solar Potential Tool which utilises the array spacing method presented. This paper also applies the methodology to a general analysis of array spacing and power density (installed capacity/unit area) for an optimally tilted equator facing array on roof surfaces of a variety of tilts and orientations.