I am planning to build a home in the Jim Thorpe, PA area in early 2013. I am interested in a log home with 1000 sq-ft on first floor(600 sq-ft with high ceiling) and 400 sq-ft with low ceiling. the loft will be ~400 sq-ft with a bathroom(window), door to a balcony and another opening for a 3x4foot window). The home will be built on a full above ground basement.

I have only spoken with one company sales person from TotalGreen in Monroe, NY. They specialize in DX systems. I have heard good thing about Direct Exchange as opposed to warter loops for small homes. I have also visited the website of Advanced Geothermal Technologies, Inc in Reading PA. I will be speaking with someone from that firm next week.
If I continue to do my research for actual manufacurers of DX systems who are the companies I should look at besides ECR and Earth Source Energy Solutions?

Thank you.

Any form of geothermal is going to be the correct choice. As allways it boild down to the skill and experiance of the installer. DX is not very popular in the mid atlantic as yet but it is gaining traction quickly.
Eric

I appreciate the quick and informative feedback. I went to your website and did a little reading on poor J calcilations. I found the article very interesting. I did not realize how much even an experienced contractor (in this case 2 independent contractors with differnet SW packages) can become a slave to software.

I see that you serve the Delaware, Maryland area.

My 'to be built' home will be in a section of PA about 100 miles North of Philadelphia at the sourthern part of the Poconos (just 5 miles south of Interstate 80).

One of the things I have to determine with a soil sample is the PH of the ground. From another website, I learned that Copper( or Copper Oxide) will not corrode if the PH is greater that 6.0 where 7.0 is the PH of pure water. I assume that a good geothermal energy company with experienced installation personel will know that a PH Calculation must be done before the DX System can be planned.

Thank you for your help.

Have a Great Christmas and New Year.

Both companies you mentioned have PH identification as part of their training and warranty compliance (I've trained on both).
I would allow competing water source dealers to bid your project as well.
While it is true that DX boasts higher efficiencies when they are running, it is also true that they require down time to let the ground catch up to their superior heat extraction. This can drop "average efficiency".
Much like the tortise and the hair, both products will get you to the finish line they simply do it in different fashion.
DX also tends to attract "newbies" since it doesn't require tools they don't already own. Definately check references.
Good Luck,
Joe

Thanx for the feedback. Having spent some time on the forums and in the feild the universal law with geothermal is... Pick a experianced contractor with a proven track record in your area and your well on your way to a happy ending to your project.
Eric

Posted By wmileo on 11 Dec 2010 08:55 AM
... a PH Calculation must be done before the DX System can be planned.

Yep, especially in your neck o' the (oak) woods where acid-lovers like
rhododendron and mountain laurel (PA state flower!) predominate.


A mosquito cried out in pain
A chemist has poisoned my brain
The cause of his sorrow
Was para-dichloro-diphenyl-trichloroethane

Yes, 7.2 or more like normal PH and if it is below 6.8 , I would start to worry. We've had DX systems go bad after 12-15 years. T

I would suggest looking at the Nordic DX GSHP. I believe they’re the best of the breed. See if you can find any other DX manufacturer that discloses as much about their product as Nordic does. They also manufacture the widest selection of DX, from monoblocks to triple function to pool conditioners.

http://nordicghp.com/


“While it is true that DX boasts higher efficiencies when they are running, it is also true that they require down time to let the ground catch up to their superior heat extraction. This can drop "average efficiency".”

We have not experienced this phenomenon although it is possible. We have our DX GSHP going on 8-years now and have done many installations. Our location is in Montreal Canada so our winters are about as severe as it gets.

SR

See if you can find any other DX manufacturer that discloses as much about their product as Nordic does.

Is there a place where they talk about maximum loop length and sizing for oil return and protecting the loop from acidic soil?

I see that they are using 410a, two stage scroll compressors and one TXV per loop.

"Is there a place where they talk about maximum loop length and sizing for oil return and protecting the loop from acidic soil?

I see that they are using 410a, two stage scroll compressors and one TXV per loop."



DX ground loops are always 100-feet long for vertical installations.

The liquid lines are 3/8” (OD) & vapour lines are 1/2” (OD) in vertical boreholes. This is enough to allow for sufficient velocity of the refrigerant at stage 1 to return the oil to the compressor.

Detailed info on cathodic protection can be found by acquiring a copy of Canadian Standards Association (CSA) CAN/CSA-C448 Design and Installation of Earth Energy Systems.

Canada has the strictest global approval requirements for the installation of geothermal heat pumps. DX is an approved methodology. A copy of CAN/CSA-C448 is well worth its price as this detailed protocol with its engineering requirements is like a course in and of itself!

Yes there is 1-TXV per loop. In heating mode all loops are used together, in cooling mode only 1-loop is used initially. When this loop gets sufficiently hot the computer switches to a rotation of the other loops while allowing the previous loop(s) to relax and recover. This also serves to ingeniously reduce the size of the condenser in the A/C mode.

Best and most flexible DX HP out there! (And may be the only DX 2-stage units on the market at this time.)

SR

"DX ground loops are always 100-feet long for vertical installations."
There are such things as 125' horizontal loops in some models.

"We have not experienced this phenomenon (ground freeze) although it is possible. We have our DX GSHP going on 8-years now and have done many installations. Our location is in Montreal Canada so our winters are about as severe as it gets."

Again not as familiar with products that aren't available here, but this is certainly true of Earthlinked (ECR).
Most of us here stress contractor over brand or type for good reasons, not the least of which is our favorite product might not be available in OP's area. All the manufacturer's of water source and DX equipment tend to overstate their efficiencies, in the case of DX manufacturers the efficiencies they state are particulary dependent on soil's capacity to convey heat (as one can't install longer loops if dry soil conditions are present).

SR you seem really enamored with Nordic. Unfortunately last I checked their distribution system in the US was virtually non-existant. Perhaps that has changed. Meantime WMILEO will have to look at different products.

j

For the record, we do install both Earthlinked & Nordic DX GSHP, as well as liquid HDPE conventional GSHPs. The consensus here is a preference for the Nordic DX system. However, despite a personal bias for the Nordic system, I do believe that properly installed, the Earthlinked system should be just as reliable and efficient.

I would prefer virtually anything installed by a good installer over my favorite equipment installed poorly. Proper installation is paramount!

SR

Joe is right - for Nordic, a distribution system doesn't exist in the US. In fact, one of the local Nordic dealers went belly up about 6 weeks ago - leaving a client or two "in the lurch." Everyone concurs, proper installation is everything. The best way to pick an installer is the three "R"'s - references, references, references.

Paul
Total Green Geothermal

Posted By Paul Auerbach on 17 Dec 2010 01:04 PM
..... The best way to pick an installer is the three "R"'s - references, references, references.

Paul
Total Green Geothermal

I like it

I actually spoke with the Brass at Nordic a year or so ago to try to get a feel for what their US plans were. A fuzzy deal with a distributor was supposedly on the horizon.
I like the idea of a company that embraces both technologies (DX and water source). Person I spoke to was excited about use of electric XV's on 2 stage DX. No other 2 stage DX I'm aware of although Earthlinked saves amps another way.
Nordic also gets very good feed back in Canada. For some reason they simply haven't been interested enough to get their "game on" here.
J

EarthLinked does have plans in the works to bring out 2-stage HPs.

Electronic TXV is the next logical step and should be a big step forward. Presently, we have specialized computers & software developed just for the Nordic DX system that real time, monitors all the boreholes as well as many parameters within the HP (Delta –T at the plenums, compressor temperature, Hi & Low refrigerant pressures, super heat & sub-cooling etc.), and the TXV’s (1-per borehole) are adjusted according to the measurements observed to optimize the system’s performance. This is done at startup and again several months later after the ground has been ‘conditioned’. It makes a significant difference in performance. I know this because when my own system was installed this real time analyzer did not exist. We only did this 2-years ago (system is 7+yrs. old). The process takes a minimum of 4-hrs per procedure, in some cases much longer.

Electronically controlled TXVs will perform this function dynamically for the life of the machine. That coupled with 2-stage compressors and ECM blowers will make this whole DX system far more efficient. It may also provide us with the data necessary to determine if we can achieve the same high efficiency with shorter ground loops, which could possibly reduce the cost of installation, particularly in areas that have a lot of flowing ground water.

It’s too bad that Nordic doesn’t have their stuff together for the US market. They’re Heat Pumps (DX or Liquid, some series up to 3-stage and 65-tons) are really well designed and manufactured for our cold climates but work well anywhere.

SR