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docjenser
Veteran Member
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| 10 Dec 2013 03:37 PM |
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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. |
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| www.buffalogeothermalheating.com |
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GreenAnythingDotNet
New Member
Posts:34
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| 10 Dec 2013 08:10 PM |
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Here's the thing: Have limited area on foundation wall that runs parallel with the garage. About 8' allowable digging trench. That would extend to loop field 135' away approx. The field dimensions itself are 200' x 100' and about 50' x 100' opposite of proposed field. Are we counting the first 135' to the loop field as any heat transference value at all ?
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docjenser
Veteran Member
Posts:1400
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| 10 Dec 2013 09:27 PM |
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Posted By GreenAnythingDotNet on 10 Dec 2013 08:10 PM
Here's the thing: Have limited area on foundation wall that runs parallel with the garage. About 8' allowable digging trench. That would extend to loop field 135' away approx. The field dimensions itself are 200' x 100' and about 50' x 100' opposite of proposed field. Are we counting the first 135' to the loop field as any heat transference value at all ?
So in the 1st 135' you can get (2) 3' trenches in, 8 ft deep. If you configure them as above, you will get a good amount of heat transfer out of them. Then you can either continue them as slinkies or racetracks. I would personally do slinkies, it saves excavation. Your call.
Do 6 trenches, 10 feet apart, have a beer, relax…. |
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| www.buffalogeothermalheating.com |
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GreenAnythingDotNet
New Member
Posts:34
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| 11 Dec 2013 06:22 AM |
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You don't loose any efficiency with slinky design ? |
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Palace Geothermal
Veteran Member
Posts:1609
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| 11 Dec 2013 08:03 AM |
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Posted By GreenAnythingDotNet on 11 Dec 2013 06:22 AM
You don't loose any efficiency with slinky design ?
NO |
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Dewayne Dean
<br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system |
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docjenser
Veteran Member
Posts:1400
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| 11 Dec 2013 06:15 PM |
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Posted By GreenAnythingDotNet on 11 Dec 2013 06:22 AM
You don't loose any efficiency with slinky design ?
WHY WOULD YOU??????? |
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| www.buffalogeothermalheating.com |
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mtrentw
Basic Member
Posts:128
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| 11 Dec 2013 08:43 PM |
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Lacking empirical evidence or experience, I would think there is some diminution in heat transfer with slinkies. Assume a 3' wide trench. STraight out and in pipe would be 2' of heat transfer pipe per foot of trench. Same trench with 3' slinkies with 18" pitch would be 8.28' of heat transfer pipe per foot of trench. I'm sure you folks who do this and have the loop calc software have a lot more insight into the thermodynamics. From a cursory perspective, it seems there has to be some impact to increasing density of radiator in the heat transfer medium. |
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docjenser
Veteran Member
Posts:1400
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| 12 Dec 2013 12:58 AM |
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Yes, you loose some heat transfer since the overlapping pipe steals some heat from each other, the effect of the higher density of the "radiator". This is why you compensate for it by increasing the overall size, usually from 600 ft/ton to 800ft/ton.
You shorten the trench from 300ft down to 100ft, but due to its wider width (over the with of the trench), the overall volume of "connected ground" remains the same, thus the performance is the same.
As a rule of thumb, 800ft 18' pitched slinky perform on par as 600 ft straight pipe.
The advantage is 100ft of trench versus 300ft. |
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GreenAnythingDotNet
New Member
Posts:34
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| 12 Dec 2013 07:52 AM |
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Cool.
The return (supply) side of the slinky is straight and laid where in relation to the coils or is another trench in order. |
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ChrisJ
Basic Member
Posts:277
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| 12 Dec 2013 10:36 AM |
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If it were me I would not drill 12 holes in my foundation. I would try to design the loop system with 2" pipe supply and return to the slinky loop field.
I am just a homeowner myself so I have no idea how to design it, but since you have a few months to research it you could learn about reverse return headers, fusing pipe, purge carts.
Chris
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jonr
Senior Member
Posts:5341
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| 12 Dec 2013 11:18 AM |
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From a cursory perspective, it seems there has to be some impact to increasing density of radiator in the heat transfer medium.
You are correct. Drawing more heat from less volume of soil has a negative effect. On the other hand, more contact area (tube to soil) of a slinky has a positive effect. So you can get good results from either. |
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SkyHeating
Basic Member
Posts:203
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| 12 Dec 2013 06:54 PM |
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One thing that is missing with a slinky is expansion and contraction. It may only be millimeters but as the waters in the loop go from 30 degrees to 80 or 90 degrees the pipe will move which would create ever so slight air pockets, couple that with needing more pipe(higher pumping cost and up front investment) and I do not see slinkies making sense. From a labor perspective my crew can install a racetrack in the same amount of time or less than a slinky and a racetrack can be placed anywhere a slinky goes, just place the lines of the racetrack closer together. I just see no reason for a slinky loop when a racetrack can be done in the same amount of space with less labor and higher efficiency. |
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Visit my Youtube channel for product reviews and customer testimonials http://www.youtube.com/user/skyheating1
http://www.welserver.com/WEL0626/
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GreenAnythingDotNet
New Member
Posts:34
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| 12 Dec 2013 07:27 PM |
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The return (supply) side of the slinky is straight and laid where in relation to the coils or is another trench in order. This was a question. Is the return(supply) line from end of slinky need to be straight and where does it go in the trench ? Top of slinky, below ? |
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docjenser
Veteran Member
Posts:1400
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| 13 Dec 2013 01:21 AM |
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Posted By ChrisJ on 12 Dec 2013 10:36 AM
If it were me I would not drill 12 holes in my foundation. I would try to design the loop system with 2" pipe supply and return to the slinky loop field.
I am just a homeowner myself so I have no idea how to design it, but since you have a few months to research it you could learn about reverse return headers, fusing pipe, purge carts.
Chris
So how do you purge the air out of 2' header pipe and without a purge cart.
You are right, I would not do it either, but I have a big purge cart, which a DIY does not have. The purpose of headering inside is mainly the ability to shut off each loop in order to increase the velocity in each circuit to get the air out. |
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docjenser
Veteran Member
Posts:1400
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| 13 Dec 2013 01:25 AM |
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Posted By SkyHeating on 12 Dec 2013 06:54 PM
One thing that is missing with a slinky is expansion and contraction. It may only be millimeters but as the waters in the loop go from 30 degrees to 80 or 90 degrees the pipe will move which would create ever so slight air pockets, couple that with needing more pipe(higher pumping cost and up front investment) and I do not see slinkies making sense. From a labor perspective my crew can install a racetrack in the same amount of time or less than a slinky and a racetrack can be placed anywhere a slinky goes, just place the lines of the racetrack closer together. I just see no reason for a slinky loop when a racetrack can be done in the same amount of space with less labor and higher efficiency.
This is all great in Theory, but at the end of the day, a 800 ft slinky performs the same way as a 600 ft straight pipe. Do you have any evidence that a slinky performs with a higher efficiency than a racetrack? Given the same amount of space.
Add on:
Meant to say LESSER efficiency. Performance similar to racetrack. Whatever is easier for you to install. I like the slinkies, easiest for me, we got the performance down. |
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joe.ami
Veteran Member
Posts:4377
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| 13 Dec 2013 09:33 AM |
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"Lacking empirical evidence or experience, I would think there is some diminution in heat transfer with slinkies. Assume a 3' wide trench. STraight out and in pipe would be 2' of heat transfer pipe per foot of trench. Same trench with 3' slinkies with 18" pitch would be 8.28' of heat transfer pipe per foot of trench. I'm sure you folks who do this and have the loop calc software have a lot more insight into the thermodynamics. From a cursory perspective, it seems there has to be some impact to increasing density of radiator in the heat transfer medium."
A typical 6 pipe race track would have 3 pipes in the bottom of a trench and another three higher in the trench after backfill. This means 1) you have 6'/foot of pipe in your trench (so depending on slinky design you may have as many or more foot/foot) and 2) a shallower average depth. Therefore the race track can be out performed by a slinky of like length.
Two things can shorten loops. Less pipe in each trench foot and greater depth. However racetracks and slinkies were developed so we could tear up less lawn during install as less pipe often means more (not less) trench. |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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GreenAnythingDotNet
New Member
Posts:34
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| 14 Dec 2013 10:09 AM |
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The return (supply) side of the slinky is straight and laid where in relation to the coils or is another trench in order. This was a question. Is the return(supply) line from end of slinky need to be straight and where does it go in the trench ? Top of slinky, below ?
Back to the subject at hand. Is there any truth as to where the supply line goes from out of the slinky end back to the main supply lines ? |
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GreenAnythingDotNet
New Member
Posts:34
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| 14 Dec 2013 03:19 PM |
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Next question, besides the earlier, what size flow center will be needed for 1330 feet of 3/4" pipe ? The loop would be 8' down and my basement is 6' out of the ground and hookup to HP is around 4'. What's the total head pressure ? Calculation sites say 153 feet of head pressure. Have I missed anything ? |
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mtrentw
Basic Member
Posts:128
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| 14 Dec 2013 03:32 PM |
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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. |
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GreenAnythingDotNet
New Member
Posts:34
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| 14 Dec 2013 04:46 PM |
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1330 linear feet per loop. What head pressure is that? And will a B&D flow center do the trick?
Model 2-230QFC I believe. Twin 230v pumps . |
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