Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: powers1976 on October 28, 2011, 01:29:35 PM
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I have two runs of about 200' each , so the pre-made stuff at 10.00 a foot is not an optionany other ideas besides wrapping the pex I'n the 5' insulation from lowes and putting it I'n corrugated pipe?
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If you are not going to use good insulation I would at least stop and start the pump if possible and also use pvc conduit instead of corrugated pipe because I would guess it would be a better insulator.
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Have you checked out insulated Pex on ebay. They have a range of prices including some available for 4 dollars a foot. I bought mine from Anderson's (through ebay) and so far I can't complain.
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I would just be careful going the homemade route, you don't want to be heating the ground, you will lose a lot of heat that way.
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Agreed. One of the biggest mistakes any DIY'er can do is install a poorly designed under ground pex line. My dealer went "cheap" a few years ago on his own install and ended up replacing his lines this summer. Lessons learned.
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Not an expert by any means, but maybe consider 2 seperate heating units placed much closer to buildings being heated. Agreed 400 ft of the good stuff would bankrupt most of us for sure!!
Best of luck,
Bill
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There has been talk on here of spray foam in the trench. Would that be viable? Hire an insulation company to lay a bead down put the pex in place and lay another layer on top. Just a thought, I have no idea what $$$ we are talking, just another option to consider.
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Expensive!!
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ball park figure here of heat loss of 1 inch uninsulated pex pipe burried inside a hollow air filled pipe..somewhere in the area of (this is a guess and likley a low ball one at that) 40 to 50 btu per foot per hour
for easy figuring lets say 50 btu per foot per hour. you say 400 feet (is that one way?) this could be 800 feet round trip taht gives us 800 x 50 btu that give us 40000 btu of heat loss per hour or 960,000 per day that in my opinion would be about wasting one years wood supply each year
now i am basing this on only guessing as i have figures for copper pipe that use an hot temp of 140 and the outside temp of 70 (1 inch copper would lose about 30 btu per foot per hour) i beleive that pex would not lose heat as fast as copper but in the scenerio we have, we would have a temp spread much larger 180 in the pipe and only about 50 in the air around the pipe and then the dirt around the air would be drawing a little ahrder as well so i say 50 btu per foot of pipe per hour is a fair number to use? (some one maybe able to do better)
these are just guesses but i can tell you this..when you see 400 feet of thawed ground in mid january that is about 2 feet wide you will say...AH HA that is where all my wood is going!
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Didn't know the $$. Mike Holmes uses this stuff like it's cheaper than air in his builds. Guess we don't have his pull or friends, huh?
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Just thought of something. Styrofoam blocks. Your state transportation testing facility most likely tests huge foam blocks for light weight fill in roadways. Cut to fit in your trench and surround your pex. I just picked up about 30 blocks of it to insulate my pole barn walls. Gave the tested blocks to me so they would not have to dispose of it, filled a 20' enclosed trailer stem to stern and they have more. Pain the the ***, but might be worth looking into. Dow or Monsanto or Dart container plant nearby? Maybe they have tested stock they would shed for free or cheap. Put it in a chipper and pour it in conduit\drain pipe.
Just my $0.01 worth of knowledge
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I used the 10' pcs of black tubular pipe insulation. It comes in big sizes so you can wrap multiple lines in it and pull it thru. I duct taped it together in places but it has a glued self seal joint also (along the split). Get it below frost line and keep the water out of the corrugated.
Is my method better that wrapping it in 1/4" material? Who knows. I also had some junk 1" board foam that I laid over the corrugated befor I backfilled.
By all means insulate it but understand that you get diminishing returns for the added cost. The question comes down to where it is best to spend the budgeted $ doesn't it?
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Just order you some good triple wrap, it's not near 10 dollars a foot. Most of it loses less than 1 degree every 50-75 feet depending on the type. I personally see little point in some of the 15 buck a foot stuff.
I wouldn't make my own, you can't even come close to making it as good as the store stuff and most people destroy it pulling it through.
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I have two runs of about 200' each , so the pre-made stuff at 10.00 a foot is not an optionany other ideas besides wrapping the pex I'n the 5' insulation from lowes and putting it I'n corrugated pipe?
Any insulation would be better than none. you will pay for good insulated pipe in wood savings alone not to mention your stove have to run doublle the amount to heat your house. Like has already been mentioned I would consider using eitherpvc conduit or sch 40 pvc pipe as a outside covering.
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You can get insulated pipe for $5-$7 per foot that it going to have very little heat loss.
If you make something equivalent it will cost you close the same or more in time and materials
The corrugated pipe is probably not very strong that Lowes sells either. (None around here but what Menards sells is much weaker than the premade insulated pex comes with)
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If I stick with a Hardy boiler, is there any downside to individually wrapping the 4 pex lines with the black foam insulation and putting it in 6" shedule 40 pipe?
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If I stick with a Hardy boiler, is there any downside to individually wrapping the 4 pex lines with the black foam insulation and putting it in 6" shedule 40 pipe?
i would make a guess that it would be likley good if you could gaurentee that moisture would not enter the pipe. if your black foam gets wet it will lose most or all of its insulation value.
and if you could make certain it would not get wet than if you warpped it twice withthe black foam i would make another guess that you would have just as good or better than the store bought stuff
if you were using black steel pipe i would suggest a pressure test of some sort to make sure it is water tight before putting your lines in it
also if the joints are screwed, wrapping them with tape to keep the moisture away from them would be benificial as well
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I recently installed my DIY pex line and currently stove temp at around 175 degress and 37 degress outside temp in 110' the pipe loses nothing. Now I'm not sure what its going to do when in gets in the single digits, but its really got me wondering. I purchased the same lowe E wrap that the manufactures use, it came in 24 inch by 100 foot rolls. I cut it in 5 20 foot pieces and got about three wrapes out of it, then strap taped the hech out of it. I used 4 inch schedule 40 as the conduit. The only thing I think i'm really going to regret is only buried the pipe 2 feet down. Like I said it works great now, we will see when it gets real cold.
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I recently installed my DIY pex line and currently stove temp at around 175 degress and 37 degress outside temp in 110' the pipe loses nothing.
all pipe loses some heat, nothing can be insulated enough to not let energy move from warm to cold. however, after saying that it may me so small of anamount you can not measure it. there is more to just insulation involved in what you call losing heat in your pipes. if say for instance if you were pumping water through your pipes at 5 gpm and notice you were losing 1 or 2 degrees at the house if you were to up your flow to say 10 gpm you may see such a little heat loss it would not be measurable
to determine the real heat loss would require you to stop the water in your pipes from flowing and measure how many degrees it cooled in a certain time period and if you could talk to the right person they could figure out the r value of your insulation.
my personal belief is if you have yoru pipes insulated and inside an air filled conduit then you have about the best you can get as the heat loss from your pipes to the air in the conduit would be far less than the heat lost from your pipes to the earth
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If I stick with a Hardy boiler, is there any downside to individually wrapping the 4 pex lines with the black foam insulation and putting it in 6" shedule 40 pipe?
This is close to the way I did my install but I used the pipe insulation that comes in 3 foot sections and then used 2 - 4 inch black corrugated pipes (2 lines per pipe) It was cheaper to buy 2- 4 inch pipes than 1 - 6 inch
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I did the same as Bull and Foamed the ends of the 4" Currugated. I thought about the 6" but there are two problems 1) more expensive than double 4's and 2) Ditch Witch barely does a 4" ditch. Corrugated 4" has a little over 4" OD. My underground run is as deep as the Ditch Witch would go and only 50' so I am comfortable with the insulation. Diminishing returns, I could pay three times as much and only get 10% better insulation. I can't see using no insulation. Remember Thermodynamics the greatest heat loss will be where the temperature differential is the highest. You might consider 4" PVC over 4" Corrugated ... I thought about it.
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i think you can make some decent stuff ,its not so much the insulation problem as it is a waterproof concern.i have a 2deg loss in 100 ' .not bad for a cost of less than 200$ ,had 6''corragated already. very sandy and water is no problem.