Are there such things as solar-powered dehumidifier units that are designed with the express intent of using the water they extract - for drinking, watering of plants, etc?
I tried googling for such things - and solar dehumidifiers do exist, but the only ones I could find seemed to be for conventional use.
Yep. There are passive structures, referred to as air wells (wiki). And there are also active [del]moisture vaporators[/del] “atmospheric water generators” ('nother wiki). Some work pretty much exactly like a dehumidifier, except they’re designed to produce drinkable water. If you’re running a condenser, it’s relatively trivial to power it from a solar panel. There are also modern methods that absorb water into some sort of salty desiccant, and use heat (sometimes assisted by vacuum) to extract the water. Again it’s relatively trivial to use solar heat in such a device.
Cool - thanks for the link - I didn’t realise there were completely passive ones.