Return to the Renewable Energy Forum | Post a Follow-Up

Geothermal efficiency

Posted by tonyzzztony (My Page) on
Thu, Aug 23, 07 at 12:12

I received a quote from the geothermal installer saying I need a 4 ton unit, 4 vertical wells (200 ft each), 2 circulator pumps @ 400 W each etc. So both pumps would be using 800 W while the geothermal unit would be using 2400W.
I asked the installer if it is possible to drill 8 wells @ 100 feet each which should require much less pumping power.
He said its hard to balance 8 wells connected in parallel.
If the loops are the same length I don't see a problem with balancing.
Another question, regarding the COP. Is there any theoretical limit for COP and how close are the manufacturers to reaching that limit? That is another important factor to consider . In the last 10 years COP have doubled. If they could double them in the next 10 years geothermal definitely will be much better than the natural gas or oil

Follow-Up Postings:

RE: Geothermal efficiency

I'm no expert on this, but that energy usage for pumping seems excessive. Have you looked into a closed loop system?

I have no clue where the COP will go in the future, but I'm pretty certain that gas and oil costs will continue to rise - and probably at an accelerating rate. I expect that in a decade GSHPs will beat gas and oil for cost, even if their COP stays the same.

RE: Geothermal efficiency

Were obviously talking closed loop here. Pumping power may be a little high. 2400W for a 4 ton GSHP system is definitely too low! 4 deeper boreholes would be preferred due to ease of installation compared to 8 shallower boreholes. 200ft. per borehole is perhaps conservative but DEFINITELY OK.
I wouldnt worry about theoretical future COP just get it in the ground now!

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Renewable Energy Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here