Do you know if the interior surfaces should be moist to begin with or does the air well dry start itself?
I'm pretty sure they can dry start themselves. Personally, I think they should be used with thermo-acoustic stirling engines. The thermo-acoustic engines could be solar powered. There are actually solar powered thermo acoustic engines being used to compress air into liquid form and the water is actually a by-product that has to be removed. I figure pop one of those on top of a wall of pipes and you have a active and passive air well.
The walls of Babylon may have been air wells.