Towards stable performance of salt hydrates in thermochemical energy storage: A review
Joey Aarts, Hartmut Fischer, O.C.G. Adan, Henk Huinink
Abstract
A review is provided on how to achieve stable performance of salt hydrates in thermochemical energy storage. For packed bed application mm-sized particles are required. Stability is divided into different levels: the (sub)crystal and powder level, individual particle (composite) level of which the packed bed is composed, and reactor level. The most prevalent stability issues at each level are discussed as well as the solutions to tackle them using encapsulation, salt in porous matrix, and shaping synthesis techniques. Various advantages and problems connected to these solutions are discussed, as well as the lessons learned from them. It is concluded that most materials lack extensive cyclic testing and powder density measurements. The most promising route identified for stabilization of salt hydrates is through the salt in porous matrix technique, using a well-defined mm-sized porous material with high interconnected porosity. • Too many materials are explored without extensive cyclic testing. • Power densities should be reported for proper assessment of performance. • Material manufacturing should be aimed towards the targeted application. • Host materials with high interconnected porosity are most promising. • Composite methods are a suitable alternative to impregnation methods.