Published at Energy Conversion and Management – Optical and thermal performance analysis of ceramic foam solar receivers in parabolic dish solar collector assemblies: The role of collector geometrical and optical parameters and absorber and coating materials

Volumetric solar receivers perform a critical role in high-efficiency concentrated solar power systems, where effective absorption and conversion of concentrated solar radiation directly determine overall performance. This study presents a fully coupled pore-scale modeling framework that integrates Monte Carlo ray tracing with direct hydrothermal simulations on silicon carbide () and alumina () ceramic foam geometry acquired by computed tomography scans. The approach accurately captures radiative propagation, absorption distribution throughout the porous structure and subsequent fluid flow and heat transfer processes — all without resorting to empirical closure relations.

A detailed parametric analysis examines the influence of parabolic dish concentrator parameters — rim angle, focal length, aperture radius, axial misalignment error and surface slope error — on the spatial distribution of solar flux and angle of incidence at a target probe surface (receiver entrance section). Results show that higher rim angles produce more intense but compact focal spots with wider angular dispersion, while even small misalignments (–0.008) or surface slope errors rapidly degrade uniformity, increase optical spillage and promote non-uniform heating.

Pore-scale simulations further reveal the impact of these radiation field variations and absorber material choice on receiver performance. Compared to silicon carbide, alumina foams exhibit lower optical efficiency due to poorer absorptivity but superior conversion of absorbed power to useful heat owing to reduced thermal conductivity limiting front-surface losses. Pyromark-coated alumina foam combines high absorptivity with low conductivity, yielding the highest optical and thermal efficiencies, elevated outlet temperatures and enhanced volumetric effect. Findings confirm that stronger volumetric heating does not necessarily improve thermal efficiency and highlight key design trade-offs for optimizing volumetric receivers.

Leonardo F. Martins, Jorge E.P. Navalho, Miguel A.A. Mendes, José C.F. Pereira, Optical and thermal performance analysis of ceramic foam solar receivers in parabolic dish solar collector assemblies: The role of collector geometrical and optical parameters and absorber and coating materials, Energy Conversion and Management, Volume 365, 2026, 121694, ISSN 0196-8904, https://doi.org/10.1016/j.enconman.2026.121694