DX Systems
Last Post 17 Apr 2012 01:45 PM by gtjp. 49 Replies.
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AltonUser is Offline
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13 Feb 2012 09:22 PM
Which Companies Make good DX Systems?  Which should I try?
Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu, 334 826-3979
DJVUser is Offline
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13 Feb 2012 09:37 PM
I looked into Earthlinked initially
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13 Feb 2012 09:44 PM
Have you also looked at Earth-to-Air (ETA)?  What is your opinion about the DX companies and their systems?
Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu, 334 826-3979
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13 Feb 2012 09:51 PM
I looked at several and none really covered my area - ( NJ ) I called Earthlinked and got alot of help from the service side of them to try and get me in contact with a local installer.
It was not in the cards as most were still too far away and wanted way more then I expected to do the system ( 84k for a 5 ton system )

My opinion was good for them - my findings seems to indicate the return was available there, the only issues I saw were possible drying of the bores, and acidic soils  but both had work-arounds - unsure about the long term aspects of it since I stopped after having no local installers.

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13 Feb 2012 10:03 PM
ETA is located in Franklin, TN but I do not see a dealer list.
 
Earthlinked has two dealers in Alabama but I would have to do extensive due diligence as usual with any new service or product.
Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu, 334 826-3979
joe.amiUser is Offline
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14 Feb 2012 08:47 AM
Trained in 2 systems, we offer none at this time.
The largest dealer of the most popular brand in MI dropped the product. His distributor picked up a water source system.
I am not suggesting they do not have successful installations, but IMHO you are better off with WF or at least water source at this time.

Among the complaints I have with the industry as a whole are the following.
1) Expensive. Both products we looked at claimed to be cheaper than water source, yet I could get a WTA heat pump and loops installed (by sub contractor) for about $500 more (didn't see ho I could excavate and install loops for less than $500).
2) Disingenuous efficiency claims (though all manufacturers of are guilty of it), we all have spoken here about the soil being the limiting feature for heat transfer DX slows to same as everybody else very quickly. As a matter of fact they tend to load heavier to allow time for ground thaw. At the end of thde day, average efficiency is similar.
3) Industry has done little to become recognized by the International Code Council or other governing codes. Currently by IRC all geo pipe is to be hydrostatically tested and DX systems would be required to have an expensive refrigerant detector in mechanical room.
4) DX manufacturers likely require a greater attention to installation, but seem to attract and unleash less experienced contractors.

They have grown in market share and have had years of oppurtunities to improve image and failed in my opinion. The technology is viable, perhaps the business model is the problem.
j
Joe Hardin www.amicontracting.com We Dig Comfort! www.doityourselfgeothermal.com Dig Your Own Comfort!
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14 Feb 2012 09:51 AM
Having dealt with 3 home owners who had their DX system installed by different installers and had compressor failures (1 developed a leak). I saw a lack of competence at the installers' level, I am also concerned about the efficiency claims. The official numbers do not indicate a higher efficiency, but I am not sure if we are comparing apples and oranges, like direct comparison between water-water and water-air COP. While in theory a simpler and more efficient system, the conductivity of the ground has trouble keeping up. The area for heat exchange is simply smaller. Thus after the initial run in period, where the efficiency looks great, one simply needs a much higher delta T to further extract the same amount of BTUs out of the smaller loops, which decreases the efficiency and puts more stress on the compressor.
www.buffalogeothermalheating.com
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14 Feb 2012 06:46 PM
Ah yes thanks Doc. Installation options are fewer with pitch having to be maintained for oil recovery (while WTA can follow grade) and field sizes can not be increased for poor soil conductivity.
Actual excavation can tear up more of the lawn as well.....with horizontals some DX asks for a 1 pipe trench/ton of 4' wide while my slinkies are 110 X 3' so while they boast smaller foot print and higher extraction with 250' vs 600-800' /ton it misleads someone into expecting a higher efficiency of the system and less lawn repair.
Joe Hardin www.amicontracting.com We Dig Comfort! www.doityourselfgeothermal.com Dig Your Own Comfort!
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14 Feb 2012 06:46 PM
Duplicate
Joe Hardin www.amicontracting.com We Dig Comfort! www.doityourselfgeothermal.com Dig Your Own Comfort!
engineerUser is Offline
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15 Feb 2012 07:40 AM
I agree with all posted by DJ and Joe. I have yet to hear of a compelling reason to embrace the technology, and there are challenges unique to it.
Curt Kinder

The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill

www.greenersolutionsair.com
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16 Feb 2012 10:40 PM
A footnote would be to consider balance sheets and track records of DX manufacturers, few are over 10 years old, under the same name and license holder.
I have never seen an unsolvable water source heat pump problem, though they can be expensive. I am familiar with DX (3 different manufacturers) systems where kitchen sink was thrown at problems to no avail.
I am also not a fan of dealer/distributor business models.

No axe to grind with the technology, but in spite of what everyone thinks, we don't make enough per install to do it twice if the system fails, so there is little to inspire me to stick my kneck out. Geo system problems (wta or dx) can bring a small company down with only 2 or 3 scrapped installs
Joe Hardin www.amicontracting.com We Dig Comfort! www.doityourselfgeothermal.com Dig Your Own Comfort!
AltonUser is Offline
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16 Feb 2012 11:08 PM
Thanks to all for their comments.  I agree, the jury is still out on DX.  Only time will tell whether the technology will be accepted.  In a separate thread I will ask for comments on a new HVAC technology.
Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu, 334 826-3979
joe.amiUser is Offline
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16 Feb 2012 11:54 PM
The unfortunate problem with "time telling" is they are 25 years into this without definative results.
Joe Hardin www.amicontracting.com We Dig Comfort! www.doityourselfgeothermal.com Dig Your Own Comfort!
Paul AuerbachUser is Offline
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22 Feb 2012 06:12 AM
For some, the "jury" may still be out on the Direct Exchange (DX) Technology.   Not for us.  I have no intention of fighting the DX vs. water loop war and offer the following: 

We've successfully installed over 130 geothermal systems in our trading area (NY, NJ, CT and PA);  about 115 DX and 15 deep well water loop systems.  For us, we're comfortable with the DX technology offered by Earthlink and Advanced Geo.  Both are small companies that we've found  responsive to our needs as designer/installer.  We have the design expertise and drilling resources to install the DX loop system.  In New Jersey we're restricted from installing DX and we've put in Water Furnace, Econar and Climatemaster systems.  They work equally well.  

This business is all about the installer.  Installed correctly, both technologies deliver on the geothermal promise; comfort, savings, peace of mind and not burning fossil fuel on-site for heating and hot water.   Yes I know that burning coal to produce the electricity is bad and negates some of the benefits, but factor in lower geothermal peak demand in summer for cooling.  And, with heating oil at over $4 a gallon in our area, people are seeking retrofits and in new construction it makes no sense to install an oil or propane system.  We understand how to put in DX and make it work.  Our earliest DX systems were installed in '07 and are still purring along happily.  We've made very few service calls for our DX systems.  I have DX in my own home (1908 Queen Ann Colonial - foamed attic and basement) and have tracked performance for the past four years.  Instead of 1800 gallons of oil to drive my steam system, I spend about $2,200 in electricity to drive my systems which includes hot water and air conditioning.  I personally save over $5,000 a year.

Because DX eliminates one heat transfer and copper is a better heat conductor, it should be more efficient.  BUT, since there are various other factors affecting system performance, I'm not prepared to make that argument.

The end result is simple.  Install the geothermal infrastructure correctly - whatever the technology, marry it to a well designed heating distribution system and everyone is happy.
AltonUser is Offline
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22 Feb 2012 08:21 AM
Paul,

Thanks for posting your comments.  Now we need to find an experienced DX installer for Alabama.
Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu, 334 826-3979
joe.amiUser is Offline
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22 Feb 2012 08:49 AM
Posted By Alton on 22 Feb 2012 08:21 AM
Paul,

Thanks for posting your comments.  Now we need to find an experienced DX installer for Alabama.

It is easier to find an experienced and talented water source installer.
Besides Paul the 2 other DX proponents that have contributed here are distributors.

Have your customers had a problem with WF or are you reacting to poor service in SWOhio (or elsewhere)?
Joe Hardin www.amicontracting.com We Dig Comfort! www.doityourselfgeothermal.com Dig Your Own Comfort!
AltonUser is Offline
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22 Feb 2012 10:38 AM
I have been a big believer in geothermal since the 1970's when I started specifying open loop systems.  My clients have used various brands of open and closed loop systems.  Most of my clients have been very happy with their units.  To my knowledge, I have had only one client that was not completely satisified with his closed-loop geothermal system.  Some of my other clients have closed-loop geothermal systems that required several trips to get the unit running correctly.  Although they are satisified now, they still tell their friends what they went through to get satisfaction.  The biggest problem is that more and more potential users are hearing about geothermal problems that take forever to get fixed.  This has been enough for some clients to turn away from all geothermal.  Some people do not want to pay that much for a system that has problems - regardless of whether the problems are caused by the unit or installation.

In the last few years, clients have been asking me to find the most efficient and reliable systems available.  That is why I use this forum, trade shows, etc. to ask about the latest HVAC technology.  Since I do not have any financial interest in any product or service, I am free to specify the latest and best.  The problem is that no one seems to know which brand or type of system is best.  

I would be much more confident in specifying brand and type of system if an organization like Consumer Reports rated units and installation.  As an individual, I have no way to know what is the most efficient and reliable.

As a general rule, I try not to use this forum to knock any product.  I do not fault anyone who does if this results from experience.  Although I may ask for assistance on this forum, I try not to reflect too badly on any brand name.  I would rather to see a problem corrected than to take pleasure in bad mouthing it.

Although I understand that HVAC maufacturers are not contractors and have to rely upon installers, I just wish there was a way to resolve problems more quickly.
Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu, 334 826-3979
Paul AuerbachUser is Offline
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22 Feb 2012 11:51 AM
Joe,

The Water Furnace and Climate Master systems perform very well and we've had no problems.  The Econar systems are a bit problematic, but nothing out of the ordinary. 

DX, despite being around for more than 20 years controls only about 3% of the market.  DX installers are harder to find.  But like any geo professionals there are good and bad ones.  We don't denigrate any technology...it's all geo.  Use the best, most experienced installer you can find.  The technology will be secondary.

Paul
www.TotalGreenUS.com

    
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22 Feb 2012 06:04 PM
Paul,

since you have that many installs, and you say you track your own performance and you have installed both DX and water sourced systems, can you actually post some performance data (not just claims)?

I continue to have trouble to understand how you can extract the same amount of heat out of half the ground without running the ground temp much lower, which then kills efficiency. If the ground is that much colder, it does not matter that copper is a much better conductor, the ground is too cold. Given your expertise and volume, it should be easy for you to monitor performance and post it on a public webpage, in a similar fashion we do this with our water source systems. That way you would make all the the DX claims transparent and support it with actual data.
www.buffalogeothermalheating.com
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22 Feb 2012 11:53 PM
Paul, I visited your webpage (www.TotalGreenUS.com) and you are making some pretty steep claims here. Among them:

"What sets Total Green ‘DX’ Systems apart is only one heat exchange transfer is required, compared to the two step transfer in water-based systems demanding about twice as much energy consumption, as well as a circulating pump and expensive deep well drilling. "

Doesn't the overall efficiency matter?

"Copper Tubing – a superior heat conductor, proven more reliable and efficient than plastic used in water based systems. "
Really, more reliable than high density polyethylene?


"Ultra efficient Direct Expansion (DX) Technology - is at least 30% more efficient than other geothermal heating systems - achieving 4.5-5.0 COP heating and up to 33 SEER cooling in real world applications. "
When I look up the COP and EER for the Earthlinked System it is reported to be 3.5 (COP) and 16 EER. How do you come up with the above numbers. SEER (seasonal) rating for geothermal heatpumps?

"Total Green ‘DX’ Geothermal Technology is the most advanced in the market, backed by years of research, design and real-world installations."

What makes it the most advanced on the market, and again, could you elaborate on the years of research. Some data would help here.
www.buffalogeothermalheating.com
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