Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.
A numerical method to couple Monte Carlo ray tracing data to a Finite Volume (FV) semi-transparent surface to allow for the determination of thermal efficiency due to an input heat flux profile and corresponding ray directions within a central cavity receiver is presented. A sample Biomass cavity receiver[1, 2] is used as a 2-D validation case to demonstrate that a CFD FV approach can be used as an accurate solution to the Radiative Transfer Equation (RTE). A 3-D representation of this cavity allows for the approximation of cavity thermal efficiency to be compared between various input heat flux profiles due to the addition of conjugate heat transfer. Results allow for deductions to be made on the benefits of more accurate representations of heat flux maps due to the point concentration of solar energy from a heliostat field. These representations of heat profiles can be used in future applications such as cavity and heliostat field optimization by creating the critical link between ray tracing and conjugate heat transfer solution methods to evaluate central tower cavity receiver designs.
