One on my obsessions is keeping the bat cave dry (or not moldy wet). Drying out an 140 year of Vienna Cellar seams impossible but managing humidity in it without using Gigawatts of energy is an interesting challenge.
This is the latest version of my dehumidifying attempts. I am sucking air in from out side through heat exchanging tubes into the dehumidifier. On the warm humid days of spring and summer the hot air will cool and dump water on the inside of the tubes which drains down into the water tank. This means I suck in fresh dry air but I can use passive and active measures to dehumidify. If the air outside is dry then the dehumidifier blows in dry air after removing a bit of the water from it making it even dryer.
I do not know if it will work but it looks like a monster so I thought I would post a picture of it.
I think I have identified the main source of water being air from outside so this controls that water source. The problem with bloking air from outside totally is that the air in the cellar is very stale and some of the time the air from outside has a drying effect. There are so many variables that effect humidity it is literally as complicated as the weather, so i do not know if I have got this right yet or just wasting my time.