Hello,

We are buiilding a new house in the next few months and I am trying to decide which system is better for us.  We live near Indianapolis, IN and have close to 5 acres of land.  How do we know which is more effective?  The earthlinked dx system or the regular geothermal system using the Climatemaster 27 Tranquility (5 tons - 2 units) .  Is their effectiveness almost the same as long as they are installed correctly by experienced installers?

We are opting for the geothermal system instead of the electric heat pumps that were suggested.

Yes, costs may vary between the two exchangers. compare ton to ton cost to construct each exchanger. check installers refrances for hapy customers.
Eric

To truly compare costs between DX and Water Loops I recommend an actual on-line comparison at
http://www.welserver.com/WEL0201/

The Live comparison comfirms DX is more efficient by as much as 30%. Since DX does not require a transfer medium circulator pump - DX is more efficient and requires less maintenance.

o.k. I will play.  What is the finished cost to install 1 ton of dx including gas charge?  cost to install 1 ton of loop vertically, circ pump, and 20% freeze protection, $1,500.00.  Giving the dx a 30% allowance on efficiency the dx system can not cost more than $1,950.00 per ton installed.  If you can get it for $1,950.00 a ton installed it is the same as a water to air.
Eric

Posted By DoGeo on 17 Mar 2011 12:36 PM


The Live comparison comfirms DX is more efficient by as much as 30%. Since DX does not require a transfer medium circulator pump - DX is more efficient and requires less maintenance.

Would you help me see how you can tell which system is more efficient based on the WEL page

We've been down this road before - I dimly recall from other threads that DX may seem to offer higher instantaneous efficiency, but during longer run times its superior heat transfer and shorter bore lengths lead to lower entering refrigerant enthalpy since it essentially supercools soil immediately proximate to its bores.

While its apparent simplicity is attractive, I'm as yet unaware of clear and convincing evidence of DX's higher efficiency / lower operating cost compared with conventional loop.

I will add that every geo system is very site and region specific. I laid on the sarcasm to point that out. I thinkk most of us avoid "blanket statements". When you are onsite you will be better able to determine the most benefit for the lowest cost exchanger choice for that specific project.
Eric

Posted By DoGeo on 17 Mar 2011 12:36 PM
To truly compare costs between DX and Water Loops I recommend an actual on-line comparison at
http://www.welserver.com/WEL0201/

The Live comparison comfirms DX is more efficient by as much as 30%. Since DX does not require a transfer medium circulator pump - DX is more efficient and requires less maintenance.

It is boasts like these that harken the term snake-oil.
It is the contention of most of us here that installer trumps brand or type.
You might convince me that a given system is more efficient in a given application, but as was said, blanket statements are ill-advised (particularly around this group).
Did you have an answer for Dewayne's question?
j

We sell both  technologies and refer to 20-30% higher efficiency based on real world comparisons of our installed DX systems and our installed deep well water loop systems.  We're not taking anything out of context.  We're comparing apples to apples.  That said,  I'm personally inclined to note ALL sites are different and certain with the small sampling (about 10 installations) there will be other installations that show a different result.  It does stand to reason that one less heat transfer, no electrical usage driving transfer medium circulator(s) and copper as the heat transfer material would lead to a higher COP. 

Paul
Total Green Geothermal

Paul,

Which DX system do you install?  And what territory do you cover?

Posted By Paul Auerbach on 20 Apr 2011 01:34 PM
We sell both  technologies and refer to 20-30% higher efficiency based on real world comparisons of our installed DX systems and our installed deep well water loop systems.  We're not taking anything out of context.  We're comparing apples to apples.  That said,  I'm personally inclined to note ALL sites are different and certain with the small sampling (about 10 installations) there will be other installations that show a different result.  It does stand to reason that one less heat transfer, no electrical usage driving transfer medium circulator(s) and copper as the heat transfer material would lead to a higher COP. 

Paul
Total Green Geothermal

Paul, how do you know the higher efficiency? Do you monitor your systems, and do you know that the load is the same between the different installs?

It does stand to reason that one less heat transfer, no electrical usage driving transfer medium circulator(s) and copper as the heat transfer material would lead to a higher COP. 

And that shorter ground loops and longer refrigerant paths would lead to lower COP.

Perhaps the difference in delta T for refrigerant to ground temperature in the DX system over the water/whatever mix in the typical geothermal ground loop changes the equation?

At the end of the day the root of every equation is the ability of the ground to convey heat. DX starts out great, then waits for the ground to catch up making "average COP" the same as every other kind (~3.5ish).
j

Hello Alton,

On the DX side we install both Earthlinked and Advanced Geothermal Technologies heat pumps and ancillary components (taps, manifolds etc.).  Both companies are proven performers in Direct Exchange and our experience with both has been quite good. 

We've developed a proprietary installation methodology and so far have worked in New York, Connecticut, Pennsylvania, Massachusetts and New Jersey (where due to local regulations we install water loop systems.)

Paul Auerbach
Total Green Geothermal
Monroe, NY
www.TotalGreenUS.com

Doc,

We monitor the systems for energy usage and compare to other systems with alike heat loads.  We're developing a more in-depth monitoring system that we can view real time on line.  For DX this will include pressures and temperatures at various points in the cycle as well as air temperatures above the coil. 

Paul

Joe - you're correct in the basic assumption.  The idea of drilling at an angle allows far more ground area between taps - and a greater thermal mass from which to extract BTU's.  This provides a small advantage.  Then take it a step further by adding water to the geothermal field as performance dips. 

Paul

I agree that adding water will allow more btus from the shorter than typical loops used in DX.

In the Southeast where I live we have some slow moving streams.  Would a DX or polyethylene geo system function well mounted about 1" from the bottom of the stream?

Posted By Paul Auerbach on 22 Apr 2011 06:54 PM
1) Joe - you're correct in the basic assumption. 
2) The idea of drilling at an angle allows far more ground area between taps - and a greater thermal mass from which to extract BTU's.  This provides a small advantage. 
3) Then take it a step further by adding water to the geothermal field as performance dips. 

Paul

1) should a left it at that

2) Sorry but; bull. Water loops can be placed as far apart as the installer desires. Not so of DX. Diagonal drilling's boast is less torn up land scaping. Frozen earth around a DX loop slows transfer from high start-up COP regardless of distance between loops (as long as they meet the minimum distance per manufacturer). Nor should we pretend diagonal installations are the only DX configuration (don't know of any in MI).

3) Take it a step further by adding heat energy (I mean water)? If greater spacing from diagonals were so advantageous, why would there be a performance dip? Wouldn't water help any kind of geo field? How do you cost the water into your COP calcs?


I don't want to bust your chops Paul, but if you want to discuss true merits of DX that's fine. Comments like those above however are the kind that are so obviously flawed one might mistake the product for snake oil.
I've commented before on the "little brother syndrome" that seems rampant in the DX world. Why must so many of it's champions artificially inflate it's merits?
j