Improving adsorption materials properties for renewable energy-driven cooling systems

Considering addressing global warming and energy crises, this work presents an alternative cooling system based on adsorption technology. The novelty of this work lies in the improvement of the adsorption properties of the commercial adsorbent AquaSorb2000 (AS2000) for the first time by a chemical method. The AS2000 is improved by mixing with ammonium carbonate and thermally treated at 500 °C in a nitrogen gas flow. The raw AS2000 and the modified (MAS2000) adsorbents were characterized by X-ray powder diffraction, FTIR spectroscopy and N₂ gas adsorption/desorption techniques. It was found that the modification led to significant surface changes. Adsorption isotherms of HFC-404A gas were investigated over AS2000 and MAS2000 adsorbents. Experimental results are fitted with Dubinin–Astakhov (D-A) and Sun-Chakraborty (S-C) equations for the isotherms and linear driving force and Fickian diffusion models for the kinetics. Moreover, the performance of the two materials is investigated for adsorption cooling systems (ADSs) using transient simulation modeling. The results showed improvement in the adsorption uptake from 0.50 kg_R/kg_AC of AS2000 to 0.99 kg_R/kg_AC of MAS2000 adsorbent. At the optimum conditions of the modified sample, the ADS performance parameters estimated by 124 W/kg specific cooling power (SCP) and 0.17 of coefficient of performance (COP) improved by 63 % and 70 %, respectively, compared to using the indicated original activated carbon material.