Solar energy storage using chemical potential changes associated with drying of zeolites

Enhancing the heat storage density of silica–alumina by addition of hygroscopic salts (CaCl2, Ba(OH)2, and LiNO3)

“…Thermochemical materials (TCMs) [28][29][30][31][32][33] offer harmful storage capacities of long time periods and are a promising way to store thermal energy by reversible gas/solid reactions. In order to take advantage of thermochemical heat storage by sorption and chemical reaction and enhance the storage density, new families of composite materials have been optimized to be used in the hydration-dehydration reaction [34][35][36].…”

Natural Zeolites in Solar Energy Heating, Cooling, and Energy Storage

“…Boiling liquid water is not a solution to this problem because its heat of vaporization is very high. This problem is even worse in some summer-to-winter zeolite storage systems that have been proposed (Close and Dunkle 1977;Shigeishi et al 1979). Once the zeolite is cooled to room temperature, such systems have no further standby thermal energy losses over any length of time.…”

“…Expanding on this idea, Shigeishi et al (1979) proposed the use of the latent heat of adsorption of synthetic zeolites for solar energy storage. They compared activated alumina and silica gel with synthetic zeolites 4A, 5A, and 13X and determined that after drying at 150°C the energy storage density of zeolites 4A and 13X is 1020 and 1370 kJ/kg, respectively; whereas, that of activated alumina is 523 kJ/kg, silica gel is 991 kJ/kg, and water at 80°C is only 250 kJ/kg.…”

Experimental performance analysis on an adsorption cooling system using zeolite 13X/CaCl2 adsorbent with various operation sequences

“…The difference in adsorption heat is another reason for the difference in cycle time. The average adsorption heat of silica gel, zeolite 13X and CaCl 2 with water vapor as the adsorbate are 46.0, 79.4 [34] and 53.4 kJ/mol [35], respectively. Zeolite 13X and CaCl 2 have higher heat of adsorption than silica gel, thus more thermal energy is required to desorb the water vapor during the desorption process.…”