Thermo-hydraulic analysis of EuroTrough-150 solar receiver with porous foam by using CFD and MCRT techniques

The application of porous medium for enhancing heat transfer within parabolic trough solar system (EuroTrough-150-PTSC) is investigated. Several configurations of porous foam with step and uniform porosity are studied. The Monte Carlo Ray Tracing (MCRT) method, the surface-to-surface model, and the Darcy-Brinkman-Forchheimer model are used for heat flux profile, radiation, and the porous medium, respectively. The simulation results show that the rebuilding of the velocity field and the absence of hotspot formation on the absorber tube are achieved by using porous insert. Moreover, the usage of porous medium decreases the thermal resistance. Using porous medium leads to an increase in heat transfer and more pressure drop. If the porous foam is used in the bottom of the absorber tube, the Nusselt number can be increased 3 times as much as the clear absorber tube, but the Darcy friction factor increases by 2.2 times, so the PEC value would be above 1. Moreover, if the absorber tube is partly filled with the porous medium, it has a better performance compared to full-porous. In addition, if the foam is made of SiC, the heat transfer is achieved more effectively in comparison to bronze.