Geo-Radiant-Pole barn Question/challenge

[Johnk]

Geo-Radiant-Pole barn Question/challenge

I think I have a unique situation/opportunity.

Here are the stats:

Location=48022 (50 miles North of Detroit)
Pole barn=50x72x14
Walls=6" unfaced fiberglass insulation, steel exterior, plywood interior
Ceiling=12" cellulose (blown) insulation, plywood ceiling
Floor:

• Plastic vapor barrier
• Foamular 250 - R-10 Styrofoam (under and around the edges)
• 3,500' 5/8" PEX on top of the foam
• 4" slab

One 10'x10' insulated garage door
One 12'x12' insulated garage door
One insulated steel entry door
Six double pane windows
One 12 zone manifold

I have a backhoe and I'm not afraid of work. My goal is to augment a biomass boiler with a geothermal field. The barn is on a 10 acre field so there are no restrictions on digging. If I can keep the place at 40-50 degrees in the winter I'll be happy; if I can take 10-20 degrees off the inside temp in the summer as well, I'll be ecstatic.

My question is:

• How long of a horizontal geothermal field would I need with heavy clay soil and a high waterline?
• What size pipe?
• How big of a boiler?

Thanks!

 

[theoldwizard1]

I can't answer any of your questions directly but, 2" of closed cell spray foam over the entire interior will make a huge difference.

If your water level is high, your frost level is deep. You need to be about 2' BELOW the frost line to get a consistent 50° especially if you a trying to !I've that heat inside that building !

 

[86turbodsl]

Building design sounds good. Are you talking about using a GSHP or just pumping the geo working fluid through your slab? Your building is just a bit bigger than my shop, i'm around 2500ft. Depending on quite a few factors, you could be anywhere from 100,000 Btu to 50,000. Depends on your target temps too. If your goal is only 40-50F during the winter, you might be able to just circulate fluid from field to floor. If you want more than that, you'll need a heat pump. Need to define the problem a bit better. Has anyone done a manual-J? Are you working with a heating contractor or rolling your own?