Ammonia dissociation for solar thermochemical absorbers

Abstract

A prototype ammonia dissociator has been constructed and operated over a wide variety of conditions, and its performance has been examined in relation to solar thermochemical absorber operation. High values of energy storage efficiency approaching unity are obtained for high values of reaction extent, corresponding to the use of high activity ammonia dissociation catalysts. There is a need for further development of such catalysts designed specifically for solar absorber operating conditions. It is shown that in order to make optimum use of the available catalyst volume, the power density profile and specific absorber design should be matched to give an essentially isothermal temperature profile along the catalyst chamber length. There is potential for a solar thermochemical absorber based on ammonia dissociation to be constructed using simple tube technology and thus within the severe cost constraints associated with solar absorber design.