In this work

a high thermal stability amino-functional ionic liquid 3-aminopropyl-tributylphosphonium glycine ([aP4443][Gly]) aqueous solution and CO2 were used as absorbent to form a new type of absorption working pair. The solubility of CO2 in [aP4443][Gly] under the conditions of 300–510 K and 1–10 MPa was fitted with the solubility data of CO2 in [aP4443][Gly]. The specific heat capacity of [aP4443][Gly] aqueous solution was tested under different temperatures which ranged from 285 to 365 K

and the enthalpy of the [aP4443][Gly] aqueous solution was calculated. The absorption enthalpy of CO2 in the [aP4443][Gly] aqueous solution was calculated using two methods

and the enthalpy of this system was obtained. Then the abovementioned data were used to calculate the CO2-[aP4443][Gly] absorption refrigeration cycle efficiency. The results show that the CO2-[aP4443][Gly]-H2O working fluid can work at very high temperatures. When the generator temperature was 393.15 K and evaporation temperature was 278.15 K

the refrigeration-cycle efficiency could reach 0.85. At higher generator temperatures

the refrigeration cycle efficiency could reach up to 0.91

indicating that the working fluid can possibly become a new type of absorption refrigerant.