breakthrough curve can also lead to less H2O adsorption, depending on the H2O adsorption capacity of the adsorbent, through a shorter adsorption step. Less H2O adsorbed leads to lower thermal input required during desorption, as less parasitic heat is necessary for H2O desorption. There is also a large impact of the CO2 LDF constant on specific thermal energy in an S-TVSA process. This is visualised in the scatter plots in the ESI Figure . The reason for this is that when the LDF constant, and hence mass transfer, is too low, the desorption of CO2 occurs so slowly that the desorption step becomes mass transfer limited. Consequently, much more steam flows through the bed due to the longer desorption step time, and more latent heat of steam evaporation is wasted. Again, this is substantiated by the fact that the largest 2 nd order interaction for the impact of LDF constant on specific thermal energy is with the steam purge flow rate.