For the purpose of a long-term heat storage system based on water sorption, a composite material consisting of CaCl2 and zeolite Ca-X (prepared by ion exchange with Ca2+ and subsequent impregnation with CaCl2 of a binder-free granulated zeolite Na-X) was prepared on a technical scale. The heat storage density of the composite material was determined in a lab-scale apparatus and showed an increase of 45% and 68% compared to the pure zeolites Ca-X and Na-X, respectively. For the zeolite Na-X, an engineering concept based on the transport of the heat storage material through a pre- and a main reactor was demonstrated in a hardware in the loop test bench.