A new composite mesoporous honeycomb material was developed to be a thermal energy storage medium that can contact the functional fluid directly. In our previous study, this honeycombed composite material acted as a promising sorption thermal energy storage medium in an open system, exhibiting a lower regeneration temperature as 80 degrees C, high volumetric heat storage density, and high stability. In the present study, a one-dimensional transient model was used to predict both the heat storage process (desorption process) and heat release process (sorption process) occurring in the open sorption thermal energy storage unit. Our model was validated using the experimental results obtained in our previous experiments, and a close agreement was observed for the sorption process. Some discrepancy was observed in the desorption process, but it has been explained. The sorption and desorption processes were simulated repeatedly for 20 cycles, whose result was also compared with the experimental result. The operating parameters of the open thermal energy storage system were evaluated to determine its operation performance. Finally, our open thermal energy storage system was assumed to be incorporated into a paint-drying system, within which the heat storage unit is regenerated for 10 h by the exhaust heat produced by a blower in the daytime and releases its stored heat during the nighttime for 14 h. The simulation result shows that almost 51.3% of the blower's waste heat can be reutilized if the proposed thermal energy storage system is incorporated. (C) 2014 Elsevier Ltd. All rights reserved.