I saw a video on spacers to keep the tubes against the wall and separated from each other. Anyone got any knowledge on these?   It sounds like a good idea but sounding and doing are not always the same.

Also for the drillers. I have clay over bedrock. Would you put a casing all the way down to bedrock?

Bore hole spacers should be avoided at all costs. It is a good idea in theory but an absolute nitemare to execute. The video you prolly did not see was the one where the 11/4 loop was being inserted into a rock bore with surface casing and as the loop went by the top of the casing all the clips got jammed up and then started flying off and threatned to put someones eye out!!
Typically casing is set into the bed rock through the overburden for a bunch of reasons, your local codes or drillers may vary.

You might ask Rehau (a 15,000 person multinational company) for customer references. Or check this, page 6 for a picture of secured clips.

http://na.rehau.com/files/RAUGEO_Brochure.pdf

Again with the rehau system?  How many have "you" installed?  How much does it cost?  Can you use part of the system?  What is the roi based on material costs vs. conventional wisdom?

I will allways trust a 15 gizillion employee multinational company that has a shiny website with no "real meat" or "data" or "cost" specified.  The website is just a slick sales brochure.  A way to cash in by re-inventing the wheel.  While we are on the topic of multinational companies I have a bunch of Toyota's with bad gas pedal assymblies for sale cheap.

Sounds like you missed the "ask" and "customer references" words.

Posted By waterpirate on 31 Jul 2010 06:48 AM
I will allways trust a 15 gizillion employee multinational company ...

Also, that "cast of thousands" argument is somewhat less impressive when viewed
in the context of REHAU AG's overall corporate footprint. They prolly have six guys
(plus a part time web designer) dedicated to the geothermal product line.

REHAU Incorporated Company Profile (Industry: Auto Parts)
REHAU Inc. is the US headquarters for the operations of German polymer products
concern REHAU AG + Co. The company makes plastic products to serve a number
of industries, including automotive, construction, furniture, and appliances. REHAU's
polymer components for the auto industry include bumpers, rear spoilers, hose
assemblies, air ducts, and sealing systems. The company produces vinyl windows
and doors and heating and plumbing components for the construction industry, as
well as a variety of piping supplies for municipal water main and sanitary systems.

http://biz.yahoo.com/ic/138/138977.html

...polymers, spoilers, doors, appliances, furniture, ...AND bore hole spacers!!!

Looby

I have contacted rehaugeo east coast sales and will have the "data" post haste. After reading their technical information it refers back to the igshpa info and the ashrae info. Both of those make no allowance for double u tubes or bore hole spacers being used to reduce anythin in the design. It is all based on geology and a conductivity testing results. I looked at this system 3 years ago?
Again the claimed savings can not be verified and we will soon find out how expensive that system really is when compared to a traditional hdpe loop and a 20% solids grout. In my common sense world you would never pile up pipes in a horizontal system so why would you do it vertically and expect a different result? I will post any communication I recieve from them.
Eric

> you would never pile up pipes in a horizontal system

Actually, almost everyone does and nobody claims that it doesn't perform better thermally. They are also careful to separate the tubes (like spacers do). Why would you expect vertical to be so different thermally? I suggest you drop the performance arguments and stick to roi or practicality issues. Or try some "ad hominem" arguments.

I suggest that you post the name and history of your geo business, your credentials, number of successfull installs, or anything proffessional which support your hours of mundane net surfing and gathering of useless information.  Do you even have a geo system in your home that you can give real data about or share experiences?

Loops nearly always impact one another due to proximity. Trick is to allow for it (design for it) and embrace the least expensive fix. Usually that will be slightly more bore hole or trench.

Rarely will it be gadgets. What some here don't understand is that the thrust of most of these products is to save the contractor- yes contractor- time. When contractors don't smell value for their customers they discard the ideas.

Again professional installers have reached conclusions on the most cost effective design for their customers.
Gadget manufacturers' and their salespeople are left to appeal to the homeowners to "ask for us by name".
Sensible people will trust the company they hire to do their installation, not internet assertions of benefit by "Widget LLC".
j

The guys at IGSHPA have actually done and published a lot of research showing that the spacers add to the performance of the loop. The problem is that they are such a hassle to install that in the real world it is quicker (and therefore more economical) to compensate for the lack of spacers by adding more length to the loop to get the same performance out of the loopfield.

4 vertical pipes versus 2 are common in Europe, where drilling costs are more expensive, pipe is relatively cheap...many things can work, it comes down to an economical balance point

It seem logical that max pipe separation and maximum sidewall contact would make the most efficient system. Better than any thermal grout which someone could call a widget. I think the borehole material is a key player. Meaning the spacer would work better in some material than others.

I wonder why the borehole pipes don have a factory insulated spacer to keep the returning water from picking up heat from the supply pipe. Imagine if boiler supply and return pipes were touching each other for hundreds of feet.

This real-world guy claims to use them on every job and provides a good idea of how much time/expense is involved. 15 seconds per clip x 20-30 clips?

http://www.youtube.com/watch?v=W4A-6lLCDN8

http://www.ghpsystems.com/GeoCli3.gif

Posted By Volleyball on 02 Aug 2010 09:59 AM 


Imagine if boiler supply and return pipes were touching each other for hundreds of feet.

boiler supply and return lines are often close together, particularly where you have a return pipe hidden within a baseboard housing. might not be the best case scenario due to the fact that it is usually all within the conditioned space.

In geo no catastrophe occurs with touching supply, return pipes or headers. If you look at the example of a slinky, most of the leaving pipe is in contact with the entering (or vice versa). Because of that, a few extra feet of trench/pipe are required, nothing more.
The benefit to verticals (cutting pipe length in half compared to slinkies) is more stable ground temps. With or without "widgets" your pipes will be just inches apart where a six pipe trench may have them 2 feet apart (but still need 2 - 3 times the pipe/foot).

As has been mentioned, some things do improve performance. Many however will not return your investment once you pay the premium to have them installed.
j

Off the top of my head (in other words, theory not tested with data or experience) I think contact between tubes degrades performance more in a vertical system than in a slinky:

In a vertical system, especially near the top of a loop, there is potential for contact or close proximity causing conduction between tubes carrying loop fluid that are at somewhat different temps (EWT vs LWT for that particular loop)

In a slinky, the contact points are close to each other relative to the path of the loop fluid, that is ~1/2 a coil diameter apart, just a few feet. So the loop fluid in the two sections of pipe in contact are likely just a few hundredths of a degree different so negligible heat transfer occurs.

All that said, I doubt heat transfer between the up and down legs in a vertical U-tube is much affected by being either in contact or separated by a space of an inch or so, especially since that inch is filled with grout intended to aid thermal conduction...

Does this make any sense to anyone else?

Of course. Any heat flow between the supply and return is short circuiting the remainder of the loop and this has a negative effect. But it's hard to avoid in a vertical loop.

The guy in the youtube video could very well be a sales pitch for the GeoClip company. He is not dressed like a driller. Plus a loop does not go down the hole that easily. And a tremie does not come out of the hole that easily. I have very little confidence in that video.

I am a driller and I personally know five other drillers who have tried GeoClips, have had a bad experience with them and will not install them. I don't know one driller who has anything nice to say about them.

No doubt GeoClips improve loop performance. There is also no doubt that they are not widely used for good reason.

That they work in theory but are not ready for real world applications makes sense. With a grout pipe several hundred feet down with those clips dragging on it could make for a nasty problem. And even if there was no extra cost to me as homeowner, I would not want to have to wait on another hole to be drilled along with the mess

I had the springy geo clips put on on my sytem in SE Pa. It was a bit of a hassle for the driller, but only added about 20 minutes to the insertion process for each 260 ft deep hole at my job site. He added a bit of extra re-bar to weight the bottom to help them go down. The issue is the outside of the clips like to snag on the sides of the hole (rough shale rock with small ledges, etc on the inside of the bore) and hinder the insertion a little. He just went a little slower and they went right in with just a few snags. No bid deal from what I saw, just lift it a little and them keep going down. We had to pre layout the whole u-bend and tremie out into the neighbors yard so everything stayed separated and did not get twisted up. The tremie stayed in each bore until gouting the next day. During grouting with the sand mixed thermal grout, the tremie came out fairly easily as the pump surges help push it up and through the clips. All in all, it is more work and a bit more time for the driller, but likely worth it in performance, but who really knows for sure how much these will help. I hope it made a difference.

You're brave to volunteer in this thread. Just kidding. :-)

Are the clips something that your driller normally installs, or did the driller/installer give you a with or without option? Also, was there an additional charge for the clips and installation (that was broken out separately)?