Development of a high accurate numerical platform for the thermal and optical optimization of linear Fresnel receivers

This paper represents an advanced methodology for the detailed modeling of the heat transfer and fluids dynamics phenomena in Linear Fresnel receivers. The present work aims at modeling Linear Fresnel elements (e.g. insulation material, glass cover, tube, pipe, etc.) by proposing a parallel modular object-oriented methodology. The heat conduction, natural convection, single & two-phase flow, and solar & thermal radiation are solved and coupled in an adequate manner. The Navier-Stokes 3D equations with incompressible and turbulent fluid hypotheses are used to solve the fluid inside the cavity by means of a CFD&HT coupling with thermal and solar radiation. The heat flux incident on the tube is analyzed by a 3D conduction model to determine the temperature distribution, single or multiphase models can be used for the HTF. A Monte Carlo Ray-tracing method is applied to obtain the estimated solar radiation source as a function of the altitude and azimuth solar angles. This work presents a comparison of three configurations, their optical behavior, the effects of the receiver height, the orientation of the mirrors and the shadows, temperature, velocity and thermal flow profiles are analyzed and presented hereafter.