Effect of porous disc receiver configurations on performance of solar parabolic trough concentrator

In this article, heat transfer enhancement of line focus solar collector with porous disc receiver is studied with water and therminol oil. A three dimensional (3-D) numerical simulation of porous disc enhanced receiver is carried out using commercial CFD software Fluent 6.3 to evolve the optimum configuration. The 3-D numerical model is solved by renormalization-group based k-ε turbulent model associated with standard wall function. The effect of porous disc receiver configurations (solid disc at bottom; porous disc at bottom; porous disc at top; and alternative porous disc) on performance of the trough concentrator is investigated. The effect of porous disc geometric parameters (φ, θ, W, H and t) and fluid parameters (Pr and m) on heat transfer enhancement of the receiver is also studied. The numerical simulation results show that the flow pattern around the solid and porous discs are entirely different and it significantly influences the local heat transfer coefficient. The porous disc receiver experiences low pressure drop as compared to that of solid disc receiver due to less obstruction. The optimum configuration of porous disc receiver enhances the heat transfer rate of 221 W m−1 and 13.5% with pumping penalty of 0.014 W m−1 for water and for therminol oil-55, heat transfer rate enhances of 575 W m−1 and 31.4% with pumping penalty of 0.074 W m−1 as compared to that of tubular receiver at the mass flow rate of 0.5 kg s−1. The Nusselt number and friction factor correlations are proposed for porous disc receiver to calculate heat transfer characteristics. The porous disc receiver can be used to increase the performance of solar parabolic trough concentrator.