A critical overview of adsorption kinetics for cooling and refrigeration systems

The dynamic uptake of adsorbate onto the porous adsorbent plays a crucial role in determining the performance of the adsorption-based cooling system. Therefore, it is imperative to know the kinetics parameters of an adsorbate - adsorbent pair to design a system to be operated at variable working conditions. The kinetics models of adsorption, used to simulate the adsorption rate of different pairs, are derived and presented in this paper. Besides, the limitations and advantages of the models are also mentioned. Moreover, the dynamic performance of different adsorption pairs is analyzed, and the values of kinetics parameters, determined through experimental procedures and fitting of kinetics models, are also summarized. It is opined that during the initial unsaturated condition of adsorption, the semi-infinite model can be preferred to determine the diffusion time constant. The modification of different models, e.g., Langmuir and linear driving force models, can significantly overcome the drawbacks of the models, as shown by several researchers. However, research may be carried out to investigate different models' fitting errors from a statistical perspective. Furthermore, to evaluate the dynamic performance of different adsorbates, a lot of research needs to be done, specifically, on the adsorption of the newly developed environment-friendly refrigerants, onto the promising composite adsorbents possessing high thermal conductivity and significantly improved adsorption uptakes.

Automated summary

This article discusses the importance of the dynamic uptake of adsorbate onto the porous adsorbent for the performance of adsorption-based cooling systems. It presents kinetics models for simulating adsorption rates, analyzes the dynamic performance, and summarizes kinetics parameters values determined experimentally. Researchers suggest modifying different models to overcome their drawbacks and emphasize the need for statistical research on fitting errors of different models, with a future focus on adsorption of new environmentally friendly refrigerants and promising composite adsorbents with high thermal conductivity.