HEFESTO: A novel tool for fast calculation and preliminary design of heliostat fields

This work introduces HEFESTO, a novel and innovative software tool conceived for the efficient estimation and preliminary design of heliostat fields in central receiver systems. The tool incorporates advanced methods for evaluating four key efficiency factors: cosine effect, atmospheric attenuation, shadowing and blocking, and spillage. A novel attenuation model based on aerosol optical depth offers enhanced flexibility and accuracy for various visibility conditions. Additionally, a new spillage estimation method leverages elliptical approximations of flux images, while a fast and efficient shadowing and blocking model significantly reduces computation times. HEFESTO also integrates reference models from the literature, such as the standard projection method for shadowing and blocking and the Hermite expansion for spillage, along with advanced solar field configurations, including biomimetic spirals and dense packing patterns. Validation using real data from 3 heliostats of the CESA-I heliostat field, ray-tracing simulations and entire field layouts with state-of-the-art design tools demonstrates strong agreement. Comparative analyses across field configurations and solar positions reveal that HEFESTO achieves up to a 10-fold speedup for shadowing and blocking (accuracy within 0.4 %) and 5-fold speedup for spillage (accuracy within 0.6 %) compared to standard methods, making it a powerful tool for optimizing heliostat field designs.