Novel ammonia sorbents “porous matrix modified by active salt” for adsorptive heat transformation: 2. Calcium chloride in ACF felt

Novel composite sorbent “31 wt.% CaCl2/ACF” was synthesised by dry impregnation of an ACF felt with a CaCl2 aqueous solution. Apparent isosters of ammonia sorption were measured at T = 20–90 °C and P = 0.1–9.0 bar by an isosteric adsorption method. The method is based on the sorbent heating in a closed volume of an adsorber with registration of the ammonia equilibrium pressure P as a function of temperature T. The uptake covered the range of 5.7–36.9 wt.%. The apparent enthalpy and entropy of the ammonia sorption as a function of ammonia uptake were obtained directly from the slop of isosteric lines lnP(1/T). Appropriate correction to obtain the true sorption enthalpy was done by taking into account the “dead” volume of the adsorber. The new adsorbent was found to be an advanced material for adsorptive chilling.