Nancy:

If you think you are verbose....

Now that it's too late to go back and do it all over again....

Before I even got to erecting my year round use Midwestern GH, I would have given far more thought to cooling than I did heating it. Not that a lot of ground insulation wasn't important for me in the land of -0 winters, but it's cooling it in summer that's proved the real headache.

Your observation regarding cooler air at ground level reminded me of why, when we leave for more than a few days in high summer, we turn the AC thermostat up and when we return, instead of lowering it immediately; turn on the big whole house fan, to have it pull the huge sink of cool air up from the basement.

In less time than it takes to unpack a carry-on, the air drops to close to our desired temp and by the time we turn off the fan and reset the thermostat, the AC unit maintains it with no extra effort.

So... if I had to do it over again, while we were excavating for water and electrical lines, I'd have run a 12 inch wide X 6 ft. deep trench from the middle and out at least 30 - 40 ft away from the GH foundation and laid in a 10" dia. PVC pipe to come up to a bit above ground level in a shady spot.

I would have screened the top, then capped it with a round concrete patio block, held about 2 ft. above the pipe with bricks, to prevent rain entry and also maintain constant shade.

Then, that pipe would have been split under the GH foundation, to lead to fan boosted floor vents, and with the big ceiling fans under the roof vents, I'd have had cheap to operate geothermal cooling.

Too costly and elaborate? Not really. A wider blade on the DitchWitch rental would have cost no more than the narrow one we used to trench for water lines and even the largest diameter 10 ft. lengths of PVC pipe, couplers, reducers and smaller sizes used as split leads up to fan boosted plastic floor vents would not have cost more than a few hundred $, and been well worth it in the long run.

I would very much like to see some photos of that and or a drawing of what you mean. Cooling is going to be my problem also.
Tks
1eyedJack and the Dawg

Dawg:

The design is only in my head, but the concept is pretty straighforward. As air passes over coils in an AC unit, the coils chill it. Now think of ground temp at about 6 ft. down. It's a constant 55 in my area, but easy to determine in yours. Then, think of the ground surrounding a deeply buried pipe as cooling coils. The larger the pipe, the more air can be moved through it, and the longer it is, the more the air will be cooled as it moves.

Bringing such a cool air pipe up to just below the floor surface of a GH foundation is simple enough- especially if you do it before framing the foundation and erecting the structure. Once the main is up to the center, use reducers to split the pipes and lay them under the floor and up to standard baseboard vents along the walls, the same as ducts/vents from a hot air furnace are configured.

However, it wouldn't work as a passive system. You need some means of pulling the air into the exterior inlet and in retrospect, my notion of using only fans at the floor vents was ill-conceived, although small booster vent fans really do help with outlet air flow.

It would be better to mount a powerful fan atop the inlet, set a foot or so above ground level. Then, it's just some math: X cu ft of pipe and a fan rated to pull the desired cu ft of air per minute.

Once the air is released inside the GH, you need a means to move it up, and as a GH has no return air ducts; out- and for that, I don't think you can beat a ceiling fan under a roof vent.

Lay a pipe deep, large and long enough and use a powerful, high volume exhaust fan and I believe you could seriously cool a GH with the only moving part being the fan.

As chilling as an AC? No, of course not, but if moving through pipes surrounded by 55 deg. ground could drop the temp of intake air even 10 - 15 deg., it could make a huge difference.

Birdwidow:

I like the idea, conceptually. But in practicality, I can't see it working that well for "me."

I do like the idea of harnessing geothermal energy for regulating the temps (I think I saw a piece on "Dirty Jobs" or some other Discovery Channel program). It looked like a really cool idea (No pun intended!).

Thankfully, I didn't have to run trenches for my GH (Electricity is only a couple of feet away, and the hose easily reaches my GH). And our soil is pure, rock-solid, cement-like clay (in the summer anyway. Winter, it's more like slimy soup!). Plus the GH is tucked (tightly) into a back corner of the yard - I don't have anyplace that I *can* run a trench (not without disrupting tree roots, anyway)

Nope. Digging ain't gonna happen! ;-)

But I hope someone finds your suggestion useful; utilizes it; and TELLS US about it!!!

I'm happy, so far, with the one screen panel. I've been able to stay w/in 12-15* of ambient since I installed it (Yay!!!).

But I've still topped triple-digits a couple of times since installation (Thankfully, not "deadly")........

My "Addition Du Jour" was a cool-air humidifier that I found for appx $23 on eBay. Duracraft DH-805. It holds 3 gallons of water and it has a fan that blows upward. Sucks air in the side, drawing it over the water-well, and blows straight up. I've got it hooked up in front of my box-fan (that lives directly in front of the "screened" window).

I hooked it up this morning, as the sun was just starting to warm things up (to 93* in the GH). Temps dropped 2* almost-immediately - and it kept the GH in a "reasonable" temperature realm for the entire day!!!

I've got the humidifier (and the box fan) hooked up to a temperature regulated plug. It turns on at appx 78*F.

So far... So good! I'll keep an eye on how it performs and post the results here...

I think this might be a better solution than the bubbly-fountain I was thinking about earlier.

Heck, for twenty-some bucks, I've got nothing to complain about!

It's not something I'd use when it's "wet" out. But when it's wet, the GH wouldn't be all that hot anyway..........

Thanks, though, for the great idea!

-Nancy