posted on 2021-11-09, 13:33authored byJian Shen, Luis Estevez, Dushyant Barpaga, Jian Zheng, Vaithiyalingam Shutthanandan, B. Peter McGrail, Radha Kishan Motkuri
Although
traditional commercially available porous carbon–fluorocarbon
working pairs have shown promising applicability for adsorption cooling,
advancements in engineered carbons may further improve the performance.
Moreover, insights into structure–property relationships that
target higher sorption capacities within these synthesized carbons
may guide such materials’ future design. We utilized hierarchically
porous carbons (HPCs), synthesized with colossal microporous and mesoporous
content characterized by high surface areas (up to 2689 m2/g) and pore volume values (up to 10.31 cm3/g) toward
fluorocarbon R134a adsorption. This unique pore topology leads to
exceptional R134a uptake, ∼250 wt %, outperforming the highest
uptake carbon material to date, Maxsorb III (∼220 wt %). Material
characterizations reveal that the outstanding R134a capacity may be
attributed to textural properties and oxygen-terminated functional
groups more than graphitization of the material. Most importantly,
HPCs are efficiently utilized in a two-bed model chiller device, where
the performance shows excellent working capacity (105 wt %, ∼2
times the value of reported carbon materials/R134a). Fluorocarbon
adsorption on HPCs also displays fast kinetics (equilibrium time:
∼2 min) mainly driven by physical adsorption (Qst: ∼27
kJ/mol), characteristic of swiftly reversible behavior adsorption–desorption
behaviors. This work provides a fundamental understanding of the applicability
of HPCs/R134a working pair for adsorption cooling.