Ammonia sorption on composites 'CaCl2 in inorganic host matrix': isosteric chart and its performance

The isosteres of ammonia sorption on new composite sorbents ‘CaCl2/γ-Al2O3’ and ‘CaCl2/vermiculite’ were measured at T = 20–90°C and P = 0.08–9 bar. It was found that the modification of host matrices by the salt dramatically increases the ammonia uptake due to the formation of CaCl2 × nNH3 complexes. The isobaric enthalpy and entropy of ammonia sorption by the salt confined to alumina pores were significantly lower than those for the bulk one. For a basic cycle, the values of COP = 0.40–0.48 were calculated at Te = −18°C, Tc = 36–42°C and Tg = 117–120°C. High COP could make these sorbents promising for application in cooling units driven by relatively low temperature heat.