(345c) Mathematical Modelling of an Enhanced Volumetric Solar Receiver Based on Partially Reflective Surfaces with a Discussion on the Volumetric Effect Criteria
AIChE Annual Meeting
Tuesday, November 15, 2022 - 1:06pm to 1:24pm
The square honeycomb receiver structure was reduced to a single channel to allow for detailed modelling of radiative phenomena. Monte Carlo ray tracing was used to model external irradiance and the conventional direct integration approach was used to model mutual irradiance. This radiative model was coupled with a 3-dimensional heat transfer model and a laminar flow model for a complete description of the problem. Furthermore, the relationship between the axial reflectivity distribution and relevant design parameters like porosity and residence time are explored via parametric sweeps, with solar-to-thermal efficiency exit gas temperature and the volumetric effect ratio as the monitored responses. This work was completed using COMSOL Multiphysics®.
The base case parametric study showed that the optimal parameters for a Silicon Carbide uniform reflectivity receiver are those of the HiTRec-II. Both varied reflectivity receiver cases considered exhibited an improvement in performance parameters for the same average emissivity of the base case. The best performance was achieved by a wall-varied reflectivity receiver, where every two walls were assigned a certain emissivity based on the amount of radiation they intersect. This receiver design is expected to achieve an increase of 5.2%, 6.1% and 8.2% in the exit gas temperature, thermal efficiency and volumetric effect, respectively, compared to the HiTRec-II.