Let's say we have an off grid home with an attached south facing walipini (underground) greenhouse.  We want to experiment with supplemental heating during the cooler months by piping warm air from the greenhouse into the house.  The problem here is the high humidity in the greenhouse, especially if it's housing an aquaponics system.  We could use a dehumidifier and draw intake air from the greenhouse, or blow exhaust into the house. Doesn't really matter.  Would a single pass through the dehumidifier bring the humidity down to an acceptable (45-60%) level?  If not, how many dehumidifiers would we need to "stack" to make this workable?

If the humidity issue is solved easily, we could even supplement heat right through the winter months with the addition of a wood stove or rocket mass heater in the greenhouse.  Plumbing a chimney outside is probably a lot easier to do in a greenhouse than installing a stove in a conventional house.

ain't got no time for dat.
Why not directly warm your home with single-pane solar heaters?




You can get a surprisingly warm stream of air from just one of these. Don't have to worry about dehumidifying it either. Probably can get 100 degree or hotter air from the exhaust of this system.

Those are cool as hell, but for this thought exercise I'm looking to utilize "existing" infrastructure.   Basically wondering if it's even feasible.  A greenhouse will get awfully hot on a clear, sunny 50 degree day.

Bumpski

One more time before I stuff this idea back in Evernote.

There really isn't a specific answer to that question - It'll depend on the type and size of the dehumidifier you use, fan speed, initial humidity level, etc., etc., etc.

Most dehumidifiers are little more than glorified air conditioners, complete with compressor, evaporator, condensor, fans, etc. - Which means that they ain't energy-stingy. You might end up spending as much operating your dehumidifier as you save by capturing greenhouse heat.

Personally, I like some humidity in my winter time heat - helps prevent cracked skin and lips, nosebleeds, respiratory infections, dry nose and mouth, etc. - and many folks install humidifiers in their heating systems specifically for this purpose.

So...why not try your heating scheme first without a dehumidifier ? You might be pleasantly surprised.

Humidity, rather the lack of it, is an issue most folks have in winter.

We have to run a humidifier just to keep at 30% most of the time in the colder months.

I'd run the air right in and enjoy it!!