Experimental investigation on properties of composite sorbents for three-phase sorption-water working pairs

LiCl/H2O and CaCl2/H2O show a great potential for sorption air-to-water and thermal energy storage (TES) with their large water sorption capacity. A concept of three-phase composite solid-liquid/gas sorption is proposed by using activated carbon fiber (ACF) felt as a porous host matrix to combine with LiCl and CaCl2. Samples with different proportions of salts and varied mass ratios between LiCl and CaCl2 are developed, and thermal conductivity, sorption kinetics and simultaneous thermal analysis (STA) are experimentally investigated. Results reveal that ACF is a better choice of matrix because water uptake and energy storage density of aforementioned samples are greatly increased. It appears that the composite sorbent of ALiCa30(3:1) is a promising material for sorption air-to-water and TES, with water uptake of 2.98 g g−1 at 25 °C and 90% relative humidity, mass energy storage density of 0.41 kWh kg−1 and volume energy storage density of 223 kWh m−3.