Optimising direct normal insolation of rectangular PV platforms

Insolation measurements recorded over decades in tropic, arid and temperate locations of Australia are used to analyse the levels of insolation falling on tracking and non-tracking platforms. The direct normal incident levels of insolation are reported as a function of solar zenith angle for several sites, making the impact of limited zenith range tracking quantifiable for standard photovoltaic, concentrated-PV and for double-layer orthogonal-offset collectors. For large field arrays of rectangular tracking platforms, the insolation losses due to mutual shading are economically significant. To minimise losses, optimum N-S and E-W spacings between the platforms are derived as a function of PV to land area ratio. The complex issue of optimal field layouts is analysed, and a methodology is given to reduce the number of parametric studies required to fine tune precise tracking platform spacings. The derivation and analysis of the platform shadow maps leads to more accurate evaluation of the mutual shading losses and assists the analysis of energy loss mitigation strategies by providing ready access to the quantum of energy lost at the collector input stage.