Solar module orientation and tracking type performance and optimization

Abstract. The efficiency and performance of solar cells and modules are typically evaluated and reported at normal incidence under peak solar radiation. We present a simple clear-sky model for solar irradiance that can be used to study the angular and annual performance of new photovoltaic materials. Using this model, we study the effect of solar module orientation for fixed-tilt module installations and different types of tracking (seasonal, 1D, and 2D) as a function of latitude. For fixed-tilt modules, the optimum tilt as a fraction of latitude varies from 0.83 at 1 deg to 0.73 at 60 deg. The effect of tilt misorientation for panels at the optimum azimuth is not very strong as the solar irradiance is about 94.5% of its optimum at ±20  deg mistilt. Both azimuth misorientation and tilt misorientation are studied. Optimized tilts and times of year for tilting are also obtained for modules that are seasonally adjusted twice and three times a year. The annual solar insolation of fixed modules is compared with modules that are seasonally adjusted twice and three times a year, continuously tracked in the north/south direction, continuously tracked in the east/west direction, and continuously tracked in two directions. The use of single-axis tracking in the east/west direction is preferable to north/south tracking and potentially improves overall energy collection by 16.2% to 31.0%. Continuous dual-axis tracking enhances overall annual energy collection by 36.0% to 45.5%. The model and provision of open source code provides for a way to assess the performance of new materials.