Optimal Design of a Silicon Carbide Ceramic Foam Solar Volumetric Receiver

Abstract

A simple procedure for an optimal designing of a silicon carbide ceramic foam volumetric solar receiver has been proposed by utilizing a local thermal non-equilibrium model of porous media and the Rosseland radiation model. Heat received from a large number of heliostats to the receiver frontal part is carried by the air as it passes through the silicon carbide ceramic foam volumetric solar receiver. Thus, complex combined heat transfer takes place within the receiver, associated radiation, convection and conduction. Sano et al. recently applied the Rosseland approximation to account for the radiative heat transfer through the solar receiver. They exploited the low Mach approximation to investigate the compressible flow through the receiver. Analytic solutions reveal that an optimal pore diameter exists for given porosity, receiver length and pumping power. The pore diameter must be larger than its critical value to reduce pressure drop and pumping power to achieve high receiver efficiency. At the same time, it must be sufficiently small to acquire a large interstitial heat transfer surface. Subsequently, there exists an optimal pore diameter for achieving the maximum receiver efficiency. In this paper, useful expressions are sought for shooting an optimal set of the pore diameter, and receiver length for given porosity and pumping power.