Posted By mtrentw on 14 Dec 2013 03:32 PM
Way off on 153' of head loss. I believe your calculation to get there assumes your entire length is in series. With a manifolded system, you need to only count the partial flow through one of your pipe loops as each of those loops will have only a portion of total flow and will all see the same pressure loss. Assuming a 6 ton unit and 18 GPM total, that means there is only 3 GPM in each of the six loops. If each loop is 800' then your pressure loss across the field will only be 1.01 ft per 100' of pipe. So your loop field pressure loss will only be 8 feet. Add a few feet for your unit, a few feet for fittings and manifold, and you will be in the neighborhood of 20 feet or less of pressure loss.

Where is 1330 ft now coming from? We were at 6 x 800, giving you 20.3 ft/hd with 20% methanol in there. If you do then 20 ft out to the unit and 20Ft back in 1.25" pipe, and add 8 elbows each way, that is another 6.8 ft/hd. Then the unit and the unit piping, at least with Waterfurnace, adds, 15.6 ft/hd. 43ft/hd if you add it all up. Doing this with a 2 pump (26-99) B&D would work well, you would get 17.5 gpm of flow out of that kind of setup. Again, 6x800 ft of 0.75" going out there.

Sorry, keep changing my mind. 1330 linear feet total per loop x 6: 265 to/fro + 800' slinky per loop.

Got a few options for slinky lengths. Wondering if I'm gaining much by adding 200' of slinky loop per ton ?

When you mean "Methanol", don't you mean Propylene Glycol ?

Posted By GreenAnythingDotNet on 15 Dec 2013 07:52 AM
Sorry, keep changing my mind. 1330 linear feet total per loop x 6: 265 to/fro + 800' slinky per loop.

Got a few options for slinky lengths. Wondering if I'm gaining much by adding 200' of slinky loop per ton ?

When you mean "Methanol", don't you mean Propylene Glycol ?

Longer loops increase your pressure drop, you are obsessed with length per ton, which will not give you much gain. Run the loops out there as I told you, and you will be fine. 800' are the max length you should go with 3/4" pipe, if you want more heat exchange area, you have to put in more circuits. The calcs I did for you were assuming methanol as an antifreeze, if you want to use propylene glycol, your pressure drop will increase even more, since PG is more viscous at colder temperatures. But you can do this, you just have to account for it.

K. Agreed on the obsessed part.

So you're saying 7 loops at 800' are much better than 6 loops at 1200'?

There are 200', 400', 600' & 800' slinky lengths. So 250' (500') to/fro house/loop field and 400' slinky, and 7 loops would work the best efficiency in my setup? Total 900' per loop.

Posted By GreenAnythingDotNet on 15 Dec 2013 06:56 PM
K. Agreed on the obsessed part.

So you're saying 7 loops at 800' are much better than 6 loops at 1200'?

There are 200', 400', 600' & 800' slinky lengths. So 250' (500') to/fro house/loop field and 400' slinky, and 7 loops would work the best efficiency in my setup? Total 900' per loop. If you want to go longer, use 1" or 1,25" pipes.

Posted By docjenser on 10 Dec 2013 03:37 PM

Posted By GreenAnythingDotNet on 10 Dec 2013 07:56 AM
Would u consider doing this if I provided the materials?

No, I don't like to travel. It is not rocket science. Nor do I do jobs where I do not supply (and control) the material
Dig a 3 ft wide trench, run it out 170ft as you have planned, put (6) 3/4" HDPE SDR11 pipes in there, then branch out for the remainder of the 230 ft into 6 trenches.
In the first 170' put (3) pipes at 8' depth, 1.5' apart. The other 3 pipes at 5-6 ft depth.
In the 6 trenches, put the lines going out on the right side of the trench, and the return line coming back at the left side of the trench, as far apart as possible.
Then you run the return lines back to the house in a second trench the same way you did run them out. Drill 12 holes, get the pipes through, seal them, put the headers inside.

May be i am missing something, but it used to be 170 out there. Just to repeat the instructions, so you get some heat out of your long header trench, running it like a racetrack, then you can breach off into slinkies and run the remainder of the 800 ft pipe as a slinky. Again, no more than 800 ft long. You can add a 7th or 8th circuit, but do not go longer than 800ft.

Ok. Will do.

Next question: the line coming back from slinky loop goes on top of slinky about a foot higher?

The return line for a slinky is part of the slinky. http://www.diygeo.com/media-gallery/detail/28/13
Does this answer your question?

Kind of hidden in the picture. Is it underneath?

It is right beside it.

Would it hurt to have it a foot above the slinky? Or alter the efficiency?

Here is a welserver site of Doc's that has a picture of a slinky loop.

http://welserver.com/WEL0267/

Chris

That's better, yet I'd still like to know if I'm gaining anything by laying the return line above the slinky?

I'll make the suggestion, instead of drilling all those holes in your foundation. Buy a 500 gal. septic tank (square is easier to work with) and bury it in the yard with a tank riser sticking up so you can access it. Then, install a manifold in there and then run your supply and return to your basement.

Still extra work and $$ for an unsafe confined space. Where water sits, will stagnate and turn into a bacterial environment. And a pain to work on without proper PPE.

Prefer the safe environment of my basement.

"Would it hurt to have it a foot above the slinky? Or alter the efficiency?"

Technically you would be raising the average depth thus reducing efficiency.

You don't have to redesign the wheel here.

Really? How so?

When the return line passes by the colder slinky lines it'll tend to grab heat from it. Theory is, heat rises, cold falls.
A foot above would eliminate that difference upon return to house. Same effect when pumping warm water through reverse in summer.

Posted By GreenAnythingDotNet on 17 Dec 2013 03:41 PM
...

When the return line passes by the colder slinky lines it'll tend to grab heat from it. ...

?

Best regards,

Bill

Posted By GreenAnythingDotNet on 17 Dec 2013 03:41 PM
Really? How so?

Theory is, heat rises, cold falls.

Yes, in air or liquid, this might be true, but not in solid matter.

Doesn't the cold lines steal heat from the returns being so close ?

And what's used to seal the holes in the foundation after placing the lines through ?

Good Lord GADN,
This ain't our first rodeo, it's yours. If we can help, great. But I personnally grow weary answering the same question repeatedly.

What to seal the holes in the basement with is a great question and you intend to have six times as many holes because you have a better plan than what we do..........

Go to the local well driller supply they have all sorts of choices. A bag of bentonite employed with backfill material is cheap insurance.