Exploring storage capacity in thermal energy storage using a combination of solid and liquid desiccant sorption media for water sorption

Abstract

ABSTRACTThe combination of solid and liquid sorption media for thermal energy storage has been explored in order to improve heat flow as well as storage capacity with respect to the incomplete space-filling of closely packed solid sorbents. Three scenarios were elucidated from which in two cases the liquid/solid combinations perform worse than the neat liquid or solid and a third scenario where the combination performs better than the separate sorbents. We identified a mixture of zeolite 13XBF with tripropylene glycol as an example for such a superior combination showing a similar adsorption curve over time as the pure zeolite or glycol. After complete saturation of the zeolite in the mixture, glycol continues to absorb water, thereby increasing the overall capacity of the system. We identified a low direct attractive interaction (dipolar and dispersive) of the liquid sorbent (tripropylene glycol) with the solid sorbent (zeolite 13XBF) as a prerequisite for improved performance.