Plumbing a remote location

[Mushroom Man]

I need to run hot water to a barn 300 feet from the boiler (one way). My calculations call for 13.7 gpm in that secondary loop.
1.5 inch PEX is very expensive.
Is it possible to use 2 lines of 1" with a "Y" at each end? I have never seen "Y"s except for garden hose.
I suppose a "T" would work but the loss would be large.

What kind of friction losses might be expected relative to the 1.5" pipe.

Anyone used this approach for a cost saving or am I deluding myself?

 

[LeonMSPT]

There's about one way to do the job right, and the rest are not right. It might work... but I've priced PEX, 1 inch and 1 and 1/2 inch...

For 300 feet of 1x1, it would cost 7,100 dollars. Double that, for 14,200 dollars to run two supply and two returns.
For 300 feet of 2x2, it would cost 10,900 dollars. You only need one. Where does the increased cost come from?

Long dollar, adding pumps and more lengths of pipe...

Volume if a function of area,

The area of a 1 inch circle is .785 sq inches. Two of them is 1.57 sq inches. The area of a 1 1/2 inch circle is 1.767 sq inches.

Double the friction loss for the two inch lines, single larger diameter line under less "pressure" (velocity) can't be on the side of two 1 inch lines, "side by each".

Might need two pumps to pull off the one inch deal. Only need one with 1 1/2 inch.

And the thing will never work the best it can with smaller diameter pipe.

Of course, there are many different ways to look at things.

Insisting on two 1 inch lines... better off to run them into and out of a manifold... 1x 1 1/2 t's into and out of 1 1/2 piping connected to heat exhangers... taking two 1 inch lines and running them into a single 1 inch pipe kind of defeats the purpose...

I need to run hot water to a barn 300 feet from the boiler (one way). My calculations call for 13.7 gpm in that secondary loop.
1.5 inch PEX is very expensive.
Is it possible to use 2 lines of 1" with a "Y" at each end? I have never seen "Y"s except for garden hose.
I suppose a "T" would work but the loss would be large.

What kind of friction losses might be expected relative to the 1.5" pipe.

Anyone used this approach for a cost saving or am I deluding myself?

 

[Dave T]

Just curious what are you running the lines to in the barn? Why don't it need a return line?Are you using an exchanger??Dave

 

[Mushroom Man]

The run to the barn is for underfloor radiant heating. I am expanding a mushroom growing facility within the barn. A line will also go to a small (600 sq. ft.) greenhouse for underfloor radiant heating.

The price for 1" O2 barrier PEX on eBay is quoted at $460.00 for 600 ft. Doubling that for my needs would be $920.00 plus insulation.

Here is the link to the 1" PEX.
(http://cgi.ebay.com/1-x-600ft-PEX-tubing-for-Radiant-Heating FREE-SHIP_W0QQitemZ270321442086QQihZ017QQcategoryZ63902QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262)

PexSupply quotes 1.5" at $1050 or $2100 for my needs.

Would the increased head justify the 1.5" stuff.

The manifold seems like a good idea.

 

[LeonMSPT]

Tough to say without crunching all the numbers, and figuring out whether or not you'd need to add in another circulator in the return line to overcome the additional head from the smaller diameter line. Have to combine all the data, including additional electricity, and then subtract the decreased efficiency in the system. For me, the idea isn't just to get something to work when I am discussing investing thousands of dollars. I want all I can get from it, subject to the rule of diminishing returns of course. Sometimes, spending to the money to get that little bit more simply isn't worth it.

It was like when I was drag racing... "Horsepower costs money. So how fast do you want to go?" Spending thousands of dollars on some small modification to get three or four more horses is silly... When you can gain ten horse for a hundred bucks, I used to do that in a heartbeat.

The math is in a post... let me look around.

https://www.hearth.com/econtent/index.php/forums/viewthread/33393/

There's the link for the thread... long discussion, and a little back and forth which is always educating and good.

Some good math in there for you to sharpen your pencil on... but the guy lays the case out pretty clearly for the difference between 1 inch and 1 1/2 inch.

Best of luck, truly, whatever you decide. Sounds like you're doing your homework, which is the first step in building something that will work, well.

The run to the barn is for underfloor radiant heating. I am expanding a mushroom growing facility within the barn. A line will also go to a small (600 sq. ft.) greenhouse for underfloor radiant heating.

The price for 1" O2 barrier PEX on eBay is quoted at $460.00 for 600 ft. Doubling that for my needs would be $920.00 plus insulation.

Here is the link to the 1" PEX.
(http://cgi.ebay.com/1-x-600ft-PEX-tubing-for-Radiant-Heating FREE-SHIP_W0QQitemZ270321442086QQihZ017QQcategoryZ63902QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262)

PexSupply quotes 1.5" at $1050 or $2100 for my needs.

Would the increased head justify the 1.5" stuff.

The manifold seems like a good idea.

The idea is to minimize restriction, it's how they do it in a regular old heating system... big pipe with little pipes going in and out...

 

[jebatty]

I need to run hot water to a barn 300 feet from the boiler (one way). My calculations call for 13.7 gpm in that secondary loop.
1.5 inch PEX is very expensive.

Close approximations:
600' - 2" at 14 gpm = 3.1' head
600' - 1.5" at 14 gpm = 12.8' head
600' - 1" at 7 gpm (2 lines) = 26' head
600' - 1" at 5 gpm (3 lines) = 14' head

Add the head for you destination radiant flooring.

 

[leaddog]

If you are running that long of a run I would surly look into having it foamed. That would probably be the cheapest insulation as getting a contractor to come in and foaming it. closed cell foam would keep the heat loss down and with such a long run heat loss can really add up. Heaterman has done alot of foam runs and has said it is superior to anything he has seen. PM him and he should be able to give you some hints.
leaddog

 

[DaveBP]

You could use this calculator that was recently posted here in another thread:

http://www.freecalc.com/fricdia.htm

No PEX option but would do for comparison purposes.

And keep in mind, the price of properly insulating such a long run is going to be high but will cost the same for whatever pipe you use. Don't be tempted to save on insulation to make up for using the larger pipe. Anybody try to sell you on bubble wrap, walk away FAST.