One-dimensional, transient modeling of a fixed-bed regenerator as a replacement for recuperators in supercritical CO2 power cycles

Fixed-bed regenerators may be a low cost alternative to recuperators for supercritical CO2 power cycles. However, the transient nature of regenerators operating in sCO(2) power cycles has not been previously characterized. This study details a one-dimensional, transient model of a fixed-bed regenerator that captures phenomena such as local fluid properties and heat transfer coefficients, entrained fluid heat capacity, and the effects of conservation of mass during process switching. The model is validated with experimental results of a 10 kWth regenerator. This comparison shows that the model predicts temperature as a function of both time and space exceptionally well. The model predicts effectiveness, heat transfer, and discharge temperatures within 5%, and predicts pressure drop and fluid carryover within 10%. This model could be used in future studies to simulate regenerators within a supercritical CO2 power cycle.