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Sellis
08-05-2005, 04:28 PM
Looking for ways to insulate hot water heating pipes underground. They will go approximately 70' from house to pond. The plan is to be able to use the house hot water heating system to heat pond if needed for medication or to increase the growing season.

I had planed to purchase pre insulated 3/4" pex pipe but having trouble with suppliers. Can not get it on time. Need by first of September.

Thinking of making a channel out of 2" Styrofoam and lying 3/4" pex pipes in channel. filling channel with expanding foam and placing 2" Styrofoam over top.

Other idea is to use a waterproof rap to insulate the pipe.

Anyone have ideas / opinions?

Stan

Ryan S.
08-05-2005, 04:52 PM
I would just by the pipe insulation that the pipe slides into.

luke-gr
08-05-2005, 04:53 PM
That was my thought....

I would just by the pipe insulation that the pipe slides into.

schildkoi
08-05-2005, 04:59 PM
My thoughts too and bury the line DEEP, below frostline otherwise it will freeze.

Are you flowing the pand water this distance in a loop or are you planning on flowing the house hot water this distance in a closed loop? 70' is kinda far. Here ares ome pictures of a system similar to what you describe.

(will add when I get home)

Sellis
08-05-2005, 06:33 PM
The water will be from an hot water furness and be close to 200*. Will have antifreeze and be at 3' deep.

The cheep slide on insulation is inefficient at high temps. It would have more heat loss through the 140' loop than in the heat exchanger.

this is similar to what I was trying to get. http://www.microflex.be/en/products/index.html
I think I calculated the heat loss at about 2000 btu for complete loop.

bbriggs
08-05-2005, 10:47 PM
A thought that occurs to me are the pipes designed for outdoor wood furnace / boilers. They're designed for this kind of application, it seems, and may be readily available.

seanmckinney
08-06-2005, 04:27 AM
The heating pipes and the insulation should themselves be inside a pipe to keep water away from them. Would it not be more cost effective to run a gas line to a small boiler by the pool? Gas mean like air, not petrol
Try browsing http://www.yorkshirekoi.co.uk/ I seem to remember quite a few heating threads on there

Sellis
08-06-2005, 09:02 AM
A thought that occurs to me are the pipes designed for outdoor wood furnace / boilers. They're designed for this kind of application, it seems, and may be readily available.

Around this part they just put sawdust in a 3' deep trench with pipes and cover. I am sure that the sawdust is a great insulator when wet :rolleyes: . I have seen one place that the snow would not stay on the ground over a setup like that.

I can not get what I want locally (very small town). Nearest place that supplies it is 250 miles away. They can not get it in time.

Stan

Sellis
08-06-2005, 09:15 AM
The heating pipes and the insulation should themselves be inside a pipe to keep water away from them. Would it not be more cost effective to run a gas line to a small boiler by the pool? Gas mean like air, not petrol
Try browsing http://www.yorkshirekoi.co.uk/ I seem to remember quite a few heating threads on there

Gas... I am Lucky I have electricity out here. LP is available in tanks but I would have to take them to town to have filled.

The house has a large hot water wood furness and an electric hot water heater for heating. Living in the woods and having large piece of land, no shortage of dead and dying trees for near free heat :) . I plan on putting in a large lake source heat pump in a few years.

With current home system I have about 100000 BTU reserve capacity in couldest weather and about 300000 BTU in spring and fall.

So... using the house heat is most efficient way for me to heat pond.

Stan

seanmckinney
08-06-2005, 12:32 PM
You cant argue with that. :yes: :yes:

mckoi
08-06-2005, 02:03 PM
When i ran the heating pipes from my garage to the pond, about 30ft, i used plastic push fit pipe, insulated with 18mm thick foam. under ground the pipes were also insulated run inside 4" plastic drain pipe burried about 20" deep.



mckoi

Sellis
08-18-2005, 04:19 PM
I can not get any insulated pipe here in time so unless someone has a better idea......

I plan to use 2" styrofoam to make a box. I will glue the bottom channel together with a thin bead of spray foam squished between joints. Then lay the pipes in the channel with a 1"x1" of foam and glue the top on.

This should be quite efficient. It will be 3' below ground.

Stan

mountainkoi
08-18-2005, 08:01 PM
The only problem with making a foam box is that with the spray in foam it may expand beyond what you think it will. The resultas will be a split box and it will no longer be water tight.
I am sure that you would be happier with armorflex pipe insulation. It comes in 6' lengths and is rubberized , and made for direct bury. The only problem will be joints.
If you are using a heat exchanger with its own pump you will not need to protect the whole thing from freezing, just the line that is outside.
What brand of pex pipe you are using? Some types are more readily available and can come pre insulated. Wirsbo is a perfect example. I have had supply problems myself with Rehau and some of the others.
I would check with a local plumber, he can probably get what you need faster and easier than you can.
Maybe he will volunteer some pointers for you also.
Good luck!!

Sellis
08-19-2005, 09:28 AM
The only problem with making a foam box is that with the spray in foam it may expand beyond what you think it will. The resultas will be a split box and it will no longer be water tight.
I am sure that you would be happier with armorflex pipe insulation. It comes in 6' lengths and is rubberized , and made for direct bury. The only problem will be joints.
If you are using a heat exchanger with its own pump you will not need to protect the whole thing from freezing, just the line that is outside.
What brand of pex pipe you are using? Some types are more readily available and can come pre insulated. Wirsbo is a perfect example. I have had supply problems myself with Rehau and some of the others.
I would check with a local plumber, he can probably get what you need faster and easier than you can.
Maybe he will volunteer some pointers for you also.
Good luck!!

The spray foam will only be used as a glue. After it is squeezed flat it no longer expands. I have used it for gluing foam before with good results.

All the push-on pipe insulations I have found are not as efficient an insulator as I would like.

The pipes will have antifreeze in them and 3' below ground so not worried about freezing. My concern is I want to heat my pond, not the ground.

Rehau was the brand that I was trying to get from the nearest decent plumbing store witch is a three hour drive away. Locally I can not get anything usable.

Local plumer.... See earlier post about sawdust as acceptable underground insulation :rolleyes:

Biggest problem is I have run out of time to get anything shipped in.

thanks
Stan

mountainkoi
08-19-2005, 08:22 PM
The only other thing might be some foil back insulation. It comes in rolls and is only about a quater inch thick. you could wrap you're whole box in it.
I know how you feel about being hours away from decent places to buy supplies.
Best of luck to you. Let us know how it works.

Cowiche Ponder
08-19-2005, 09:01 PM
will you be able to measure your btu loss on the 70' run to the pond and back? It would be interesting to see how well the foam worked! I think it looks like it should work pretty good!

Cowiche Ponder
08-19-2005, 09:02 PM
The water will be from an hot water furness and be close to 200*. Will have antifreeze and be at 3' deep.

The cheep slide on insulation is inefficient at high temps. It would have more heat loss through the 140' loop than in the heat exchanger.

this is similar to what I was trying to get. http://www.microflex.be/en/products/index.html
I think I calculated the heat loss at about 2000 btu for complete loop.

Can the foam insulation stuff take 200* heat and not melt?? :thinking:

Sellis
08-20-2005, 06:50 AM
Can the foam insulation stuff take 200* heat and not melt?? :thinking:

200* Fahrenheit = 100* Celsius

No problem. Done it before.

Stan

Sellis
08-20-2005, 06:57 AM
will you be able to measure your btu loss on the 70' run to the pond and back? It would be interesting to see how well the foam worked! I think it looks like it should work pretty good!

I can do this once everything is finished. I would need to bypass the heat exchanger in filter pit and run the hot water through loop until it equalized then measure the water flow rate and temp out from house and return. With the difference in temp and flow the BTU is easily calculated.

Stan