Concentrated solar flux modeling in STP

A solar power tower (SPT) involves a heliostat field, which follows the sun across the sky and reflects solar radiation onto a receiver located at the top of a tower. These power plants are generally equipped with tanks to store the thermal energy for several hours before being converted into electricity. The design of an SPT requires an upstream modeling to ensure that the power generation requirements are met. One of the most important steps in the design of an SPT is the modeling of the collected radiant flux and its distribution on the surface of the receiver. The solar radiant flux collected by the receiver depends on the position of the sun, the temporal variability of the atmospheric components (clouds, gases and aerosols) and the geometric design (heliostat position, curvature, …) of the plant.

Current tools collecting solar radiant flux require approximate models to evaluate the circumsolar contribution and the impact of aerosols. HYGEOS study, made in collaboration with the LOA of University of Lille, the PROMES laboratory of CNRS and the LMAP of University of Pau and Pays de l’Adour, presents a new method to quantify such influences of the atmospheric scattering on the concentrated solar radiant flux available at the receiver. Then, it goes further in the accuracy refinement of the electricity production (e.g. SPT design and operation) to make them bankable.

The paper Moulana et al. 2024 describes how an atmospheric radiative transfer Monte Carlo code is modified to solve the radiative transfer both in the atmosphere and within the concentrating system consisting of the heliostat field and the receiver. This new model allows the estimation of not only the optical losses but also the gains due to atmospheric and environmental contributions i.e., radiant flux from circumsolar, aerosol scattering, ground reflection, etc.

Moulana, M., C. Cornet, T. Elias, D. Ramon, C. Caliot, M. Compiègne, Concentrated solar flux modeling in solar power towers with a 3D objects-atmosphere hybrid system to consider atmospheric and environmental gains, Solar Energy, Vol. 277, 15th July 2024.