Heat transfer and fluid flow analysis of a 4 kW solar thermochemical reactor for ceria redox cycling

A solar reactor consisting of a cavity-receiver containing a reticulated porous ceramic (RPC) foam made of CeO 2 is considered for effecting the splitting of H 2 O and CO 2 via a thermochemical redox cycle. A transient 3D heat and mass transfer model of the reduction step is formulated and solved using Monte-Carlo ray-tracing coupled to computational fluid dynamics . Experimental validation is accomplished in terms of measured temperatures and O 2 evolution rates obtained with a solar reactor prototype tested under high-flux radiative power inputs in the range 2.8–3.8 kW and mean solar concentration ratios up to 3024 suns. Critical temperatures of up to 2250 K induced CeO 2 sublimation, which in turn affected detrimentally the solar reactor performance. The model is applied to analyze an improved geometrical design with alternative flow configuration , enabling more uniform radiative absorption and temperature distributions , and resulting in a higher solar-to-fuel energy conversion efficiency .