Fully coupled transient modeling of ceramic foam volumetric solar air receiver

Ceramic foam is a promising material for the absorber of volumetric solar air receiver in concentrated solar thermal power (CSP) plant. The transient behaviors of volumetric solar air receiver are crucial to the receiver’s controllability, and to some extent, the plant’s safety. This study numerically analyzes the transient behaviors of volumetric solar air receiver under various working conditions. A fully coupled transient model of the volumetric solar air receiver is developed in this paper. The pressure drop of the absorber, the interfacial heat transfer between the flowing fluid and solid, and the radiative heat transfer due to concentrated solar radiation absorption by ceramic foam and the radiation transport inside the media were included together in this transient model. In addition, the temperature fields of the fluid and solid phases were obtained by using the local thermal non-equilibrium model. A comparison of the computed results with experimental data shows that this coupled transient model can be used to predict the performance of volumetric solar air receiver. Based on this model, the transient behaviors of the solar air receiver under a sudden heat flux, a sudden loss of heat flux, and a step change of heat flux were studied. The results of this study are very helpful in designing and controlling volumetric solar air receivers.

► A coupled transient model for volumetric solar air receiver was developed.
► Under sudden heat flux changes, transient behaviors of volumetric solar air receiver are studied.
► Volumetric solar air receiver’s reaction time to heat flux step is about 30–70 s.
► Volumetric solar air receiver reacts to heat flux changes smoothly.