No abstract

Heat mitigation for large-scale solar photovoltaic (PV) arrays is crucial to extend lifetime and energy harvesting capacity. PV module temperature is dependent on site-specific farm geometry, yet common predictions consider panel-scale and environmental factors only. Here, we characterize convective cooling in diverse PV array designs, capturing combined effects of spatial and atmospheric variation on panel temperature and production. Parameters, including row spacing, panel inclination, module height, and wind velocity, are explored through wind tunnel experiments, high-resolution numerical simulations, and operating field data. A length scale based on fractal lacunarity encapsulates all aspects of arrangement (angle, height, etc.) in a single value. When applied to the Reynolds number Re within the canonical Nusselt number heat transfer correlation, lacunarity reveals a relationship between convection and farm-specific geometry. This correlation can be applied to existing and forthcoming array designs to optimize convective cooling, ultimately increasing production and PV cell life.

No abstract

Accuracy in photovoltaic (PV) module temperature modeling is crucial to achieving precision in energy performance yield calculations and subsequent economic evaluations of PV projects. While there have been numerous approaches to PV temperature modeling based on both the steady-state and transient thermal assumptions, there have been few attempts to account for changing convective cooling on PV module surfaces resulting from changes in the PV system layout. Changes in system row spacing, in particular, can have a meaningful impact on module electrical efficiency and subsequent economic performance, even when considering additional costs from the changes in row spacing. Using a heat transfer approach based on the spatial definition of a PV array, technoeconomic analyses of different plant configurations are presented here that show an improved system levelized cost of energy (LCOE) for fixed-tilt PV systems when increasing system row spacing. These LCOE improvements have been found to be as high as 2.15% in climates characterized by low ambient temperatures and higher average annual wind speeds in U.S. climates. While the LCOE improvements are primarily driven by incident irradiance changes for altered row spacing, the waterfall analysis of the different components of changing system LCOE show that modifications in the heat transfer dynamics have a 0.5% contribution to the LCOE reduction for the largest LCOE, compared with a 3.3% reduction from irradiance changes.