NTXbiofuel,
bh20 is manufactured by geopro. If you want definitive answers to your grout query direct from the manufacturer of the product your driller plans on using. You are right in your assumption of "insignificant differance". Geopro's position is that if a 20% solids content is standard and adequate, increasing to a .88 is an increase of 100%, anything beyond that is belt,suspenders,braces, and the kitchen sink.
Keep us posted and let us know how it all turns out, and your wel number when you get it.
Eric

Climatemaster software indicates about a 10% reduction in required bore or ~30' (for a project I'm working on) if you were to employ two 3/4" u tubes per bore versus 1 (which is standard around mid MI). That certainly would save a couple bucks on drilling.
Operating cost is identical.
Trouble is the loop labor is nearly double, as is loop material and brine expense. Looks like you might spend a grand or two to save $300 (in my neck of the woods).

Can't say I've spent a ton of time on research in this. I tend to trust that Climatemaster has, since they guarantee results if I follow their design software.

Things that claim to enhance heat transfer are pushed to installers, not end users. Enhanced products, spacers, double dip wells are often fabulously more expensive to install with little ROI (though they promise to save the installer time to "pay for themselves"). Ridicule or avoidance of local practices is counterproductive as well since anything you want done differently will fall under the "extra" category (extra time, extra cost).

I can't even comment on some folks who spend a lot of time researching every curiosity or assertion about different loop designs and criticize experienced pros without ever having installed a system or been responsible for performance themselves. They might be harder to spot as they pretend to take the high road.
j

I'm not surprised that HP manufacturers confirm my statements about improved performance - and that they don't require thermal testing to support the reduced length that double U-tubes allow.

Thanks for confirming my statement about costs and practicality issues:

"At what point it becomes impractical (ask your driller) or non cost effective (do the numbers) is another issue."

When someone ignores the meat of a blog and suggests it supports their conclusion, their research will always be suspect.
j

So...while I might have been a tad bit out over my skis with the statement that more than one U-tube per bore is lunacy...

Do we have general agreement among the boots-on-the-ground professionals that neither multiple U-tubes per bore nor installation of tube spacers provide useful benefit anywhere near in keeping with the cost and difficulty of actually properly implementing either?

When and if I get a reply from rehau in regard to cost, shipping, install time I will post it up. In Joe's kneck of the woods a reduction of 30' per bore is indicated. So if he inserted two 120' loops plus spacers and thermal grout in a "here is the kicker" a larger diameter bore than standard. The cost per foot to drill may actuallly be more than the cost for 150' of smaller diameter bore.
The whole double u bend was born out of the rock drilling world, where it makes sense. The diameter of the hammer required to drill a given bore in rock is sizeably larger than any mud rotary bore. so if you are paying x per foot to drill no matter what the size of the loop, a sharp engineer born the idea of lets fill the whol e hole up with loop and see what we get.
When drilling mud rotary the same is not true. You can drill any size bore you want that is larger than the diameter of the rods. If you increase the size of the bore you increase the cost per foot to drill.
Yes I am in agreement that doubles and spacers add cost that is not recovered in any savings when doing mud rotary work.
Eric

Posted By engineer on 01 Aug 2010 09:59 PM 


Do we have general agreement among the boots-on-the-ground professionals that neither multiple U-tubes per bore nor installation of tube spacers provide useful benefit anywhere near in keeping with the cost and difficulty of actually properly implementing either?

I'm sure I agree. Frankly as a more practical point, I'm not the driller or loop installer, so if some poor sap in my area buys into either (multi tube bores or spacers)and insists, I would simply ask the well driller how much more and pass along the cost. There would be no savings on installation or op cost.

Curt, I can't speak about everywhere, but the reason I sense multi tube wells work here is ground water. As far as working well.....10% of the bore off; for nearly twice the loop and pump energy....sounds like lunacy to me.
j

Direct from the manufacturer (Black Hills) web site, BH20 grout is recommended "where thermal performance is not an issue". They make other grouts if you care about performance.

No smoking gun here, contractors deliver geo as inexpensively as they can to the buyer without comprimising performance. Loop spacers fancy grout and fairy dust all cost more than they save on most resi applications around here.
Remember in this loop context the goal is to achieve desired EWTs. When a few extra feet of loop can deliver same op cost for less trouble or expense, contractors will do that every time.
To suggest that this is somehow inferior shows a lack of understanding of the loop performance conversation in general.
j

Posted By joe.ami on 02 Aug 2010 06:10 PM
Loop spacers fancy grout and fairy dust all cost more than they save on most resi applications around here.

Just asking - is this based on data you have?

Posted By joe.ami on 02 Aug 2010 06:10 PM
Loop spacers fancy grout and fairy dust all cost more than they save on most resi applications around here.
Remember in this loop context the goal is to achieve desired EWTs. When a few extra feet of loop can deliver same op cost for less trouble or expense, contractors will do that every time.
To suggest that this is somehow inferior shows a lack of understanding of the loop performance conversation in general.
j

I am a driller and I agree with Joe.

> Just asking - is this based on data you have?

So much discussion about cost without any actual cost figures. Purely for the sake of having some numbers to discuss (ie, I still have no opinion on the cost issue*), here is what GeoClip claims:

http://www.geoclip.com/savings.html

* - other than that all contractors will NOT always look out for your best interests, but nobody would believe that anyway

Posted By jonr on 02 Aug 2010 10:26 PM


* - other than that all contractors will NOT always look out for your best interests, but nobody would believe that anyway

jonr,

are you asserting that if I don't install GeoClips for my customers that I am not looking out for their best interests?

If so you are flat out wrong.

 A typical  loop design might call for 1000' of bore and my price is  $14,000.

If I added GeoClips,  I could then drill 900'  but with the cost of adding GeoClips, the price is still $14,000,  how am I cheating the customer?

You are obviously a smart guy.   You have obviously never installed GeoClips.  I doubt that you install Geo Systems.  Why do insist on challenging the professionals on this forum who do install Geo Systems?

Of course not - no idea how you came up with such a straw man. I challenge the installation and drilling types when they come up with stuff like "thermally enhanced grout doesn't perform better thermally". Or I question "this costs lots more than it is worth but I don't have any figures that support this claim". The latter may even be true, but "absent data you have only an opinion" and it's not helpful for others in situations where it may well be cost effective.

Jonr,
since you can obviously find your way around the intra-net, and believe everything you see and read, please google geopro grout. When you get there click on the borehole calculator and fill out the sheet correctly and let us know what you get for data. Thermal enhancement vs. cost per foot to drill. Then pony up 1k dollars and take the igshpa design installer course in the major city of your choice. After class since you are such a nice guy take R Carda down to the pub and discuss geo and grout at length as it applies to real world application.
Then you will be on your way to helping someone to decide when thermally enhanced grout is important and when it is merely adding cost.
Do you know how much a bag of bh20 costs? How about tg lite? How about thermex? How about high silica content sand? Delivery? Labor?
If anyone from Rehau ever calls or e-mails me I will address the costs associated with double u bends and return on investment.
Just so it is clear in your mind. When Chuck Norris needs grout, he calls me.
One last querry. Are you the same jonr that has been censured other places on the web? Or is your handle and lack of posting of any credentials of any kind just a coincedense?
Lets get real, I am going to stop feeding you.

"At what point it becomes impractical (ask your driller) or non cost effective (do the numbers) is another issue. "

You seem to have some persistent belief that this isn't my statement about costs and roi. Not sure why you believe something so different, especially when I keep repeating it.

I generally ignore ad hominem, straw men, ridicule and personal attack fallacies, but you are free to try them if you want to appear unprofessional. Or maybe you can share the numbers you collected from holes with enhanced grout or double u-tubes or clips. Or discuss your engineering degree that might help with such analysis.

I'm not taking sides here, but I was also thinking of engineers phrase of "Absent data, you have only an opinion." That said, I don't believe that data presented by a company touting the benefits of its product is above reproach. Nor do I believe that even if the data is accurate, that it would be cost effective in all (ground composition, labor markets, etc.) situations.

IMO, IF I was interested in these spacers (as a homeowner) I would ask, and put faith in, my loop installer, whose references I would have already checked. I wouldn't shorten my loop as a result of using these clips but depending on the additional cost, and if the installer is willing, I may give it a try for possibly an additional loop benefit. I would also weigh this cost against just installing additional loop (instead of using the spacers). If the installer has concerns about using them, I would defer to their professional judgment and not use them. They are the ones that should "own the loop" and guarantee the loop results.

While I agree that the average home owner should just ask for references, price and the written performance guarantee, this thread started with:

"I'm a civil engineer by trade and enjoy "heavy" reading".

How might this change the discussion?

> I don't believe that data presented by a company touting the benefits of its product is above reproach.

I agree, but ditto for "data not presented by an individual touting his experience or services".

Geome,
I have experience. The support of my peers here and the loop contractors who work for me as well.
Once again. EWT is the point, how you achieve it is not.
Gadgets suggest same EWT with less loop, not lower op cost for the consumer. If you accept that point, the other 4 pages of this thread are moot.
I deliver loops to my customers at the lowest price available to me. If spacers delivered the same EWT at a lower price, I'd buy.
Folks may ask a mechanic when considering an auto purchase. They trust a mechanics experience. It's the car salesman or the automanufacturer that is asked for quantifiable data.
I'm "just a mechanic". We'll let someone who isn't busy installing systems find lots of supporting data for his contrary posistion.

J

Posted By joe.ami on 03 Aug 2010 11:45 PM

EWT is the point, how you achieve it is not. Gadgets suggest same EWT with less loop ...

Also, "same EWT with less loop" at the beginning of the season
might not look so attractive at the end of the season. Shortening
the loop also reduces the mass & volume of the heat source/sink.

Bore thermal resistance ain't necessarily the limiting factor --
and my unsubstantiated, data-free guess is that it's seldom the
limiting factor.