Prior to the first measurement run of a new packed bed, the reactor is cleaned of any residue from previous experiments. Subsequently, the reactor is filled with two batches of liquid dry water, each consisting of 600 g of water and 30 g of pyrogenic silica, and then sealed using a torque wrench. After covering the reactor top with thermal insulation, the dry water is solidified and cooled to the designated experimental temperature using the cryostat.