Abstract: In reheating and conveying a granular heat carrier, such as sand, using a carrier gas, where the heat carrier may be utilized for desorption by heating a charged lumpy adsorbent, the heat carrier is circulated through a vertically arranged cycle loop. Initially the heat carrier is conveyed from a carrier gas inlet at the lowermost part of the loop to a separator at the uppermost point. After separation, the heat carrier flows downwardly under the effect of gravity through the loop passing, in turn, through a heater, a desorber where it is mixed with the adsorbent, and another separator where it is separated from the adsorbent, before the carrier returns to the carrier gas inlet for repeating the cycle. If sand is used as the heat carrier it can be conveyed upwardly through the loop by compressed air.