Quote:
Originally Posted by superlen
AC, Thanks for the warm welcome.
I'll start collecting some pics of the system I'll be working on and the options I have. I have too many options and ideas (each with their own pros/cons) and I would love some feedback from the group on them.
I'll post a new thread in the future, but here are some basics of what I'm working with:
- 4200 sq ft (2200 main floor, 1000 2nd story, 1000 basement)
- wrapped in 6" of foam (r36 walls, r60 ceiling, low air leakage, half of basement is below grade)
- NW Arkansas moderate climate (4500 hdd)
- staple up radiant 1/2" o2 pex for 2200 sq ft main floor. (all parts bought, not installed yet - originally no spreader plates planned but that seems to be a hot topic here.  )
- 140Kbtu wood boiler (not plumbed but set in place)
- fireplace insert (primary heat now & will keep the main floor comfortable)
- 70 acres of free wood.
- Artesian Spring 50ft from house ( 3gpm min (august), max 100'sgpm after hard rain - 55deg)
- 6000 gallon holding tank for spring
- access to multiple 350-500gallon tanks
- 150 ft well (used for swimming pool and vegetable garden - at one point would continually flow 15gpm indefinitely, but has some issues now and probably needs to be redeveloped)
- Abandoned 5 ton loop field 200ft from house. (5 parallel - 300ft loops of 3/4" pex )
- 2 acre pond 1000' from house.
- surplus 5T coaxial HX from GSHP I ran several years ago.(currently plumbed in as a desuperheater on the air conditioning condenser)
- several spare 4t and 5t compressors/ condensers/evaporators/txvs/ect.
My plan is to utilize the spring and/or the well as evaporator heat source for a WTW heat pump. The radiant floor would then be the heat sink for the evaporator.
Thats enough for now and I don't want to cloud up this thread.
Len |
Sounds like you've lived in the house for a while. You spelled out a lot of info except what the heat load for the house is... which is the
most important part.
Quote:
Originally Posted by superlen
Abandoned 5 ton loop field 200ft from house. (5 parallel - 300ft loops of 3/4" pex )
|
WTF?!? Do you know anything about this?? From your specs, and not knowing the characteristics of how it was put in, or the potential of the soil in your area, it doesn't seen to me that you could get 5 Tons from such a layout. But even if it was not able to deliver 5 Tons, with the insulation you described, and a
high efficiency floor, I wouldn't think 5 Tons should be required.
However if it is in good shape (a
properly installed loop field should last hundreds of years) I would say that you should start there. You will not need to battle a constant invasion of particulates, for instance. Get it working, and then see what else is required.
Regarding your staple up floor... without plates,
the only thing worse would be suspended tubes. Even with plates, there is a problem.
With the exception of the wood burning fireplace, all of the potential heat sources you cited, are in a class known as
Low Temperature Heating Sources (=< 120F).
This means that they will not be able to reach the temperatures needed by a staple up PEX floor (180F). even if you put in lots of thin aluminum plates it might lower the feed temps (140-160F). But your Low Temperature sources will deliver lots of heat for cheap at a lower temperature (=< 120F).
If you totally bit the bullet, and built your radiant floor on top of your existing floor (spacing the PEX closer to maybe 6" to 8" AND STILL USING PLATES), then your Low Temperature Sources would thrive.
There's a lot of knowledge in the radiant heating industry, but not all of it has trickled down to the installers, who often double as designers, yet. Many of them are still designing floors for fossil fuel (=>180F) and then combining those designs with Low Temp Sources (=< 120F), and the result is
gnashing of teeth and wailing in the outer darkness.
I'd also suggest that if you can get even more insulation into the attic, it would be money well spent.
And find out what the heat load (A/C & Heating) is of your house.
Best,
-AC