Non-equilibrium sorption performances for composite sorbents of chlorides–ammonia working pairs for refrigeration

• Non-equilibrium Clapeyron curves of chloride–ammonia working pairs are bivariant.
• Desorption hysteresis of working pairs is related with desorption enthalpy.
• D-A equation and Arrhenius equation are used for simulating sorption performance.
• Established models have higher precision for simulating refrigeration performance.

The sorption/desorption characteristics under the non-equilibrium conditions are extremely important for the refrigeration. The experimental test unit is set up, and the p–T–x curves of different working pairs are tested under the non-equilibrium working conditions. The results show that non-equilibrium sorption/desorption processes are related with dual variables rather than a single variable. Then we tested the isobaric sorption/desorption processes of chlorides. Results show that the hysteresis phenomena are related with the desorption enthalpy. Sorption/desorption dynamic models are studied. For sorption process the model is in accord with D-A equation, but for the desorption process both D-A equation and Spinner model should be considered. The Arrhenius equation is used to fit the relation between reaction heat and desorption hysteresis. The results show that the non-equilibrium equations fit the refrigeration performance well, whereas the theoretical equilibrium curves have big error.