looking for geo thermol heat pump info

hello all
I found info on geo thermol heat pump loop length in this group befor. now I am ready to dig the trench now and cant find the info. can any one point me to a therad or a websight to to help me figure how long to make the loop? for waht its worth I am in the northern US, looking at 3 1/2 tons and using pex tubing for the loop.
Another concern I have is we have a lot of rock here so I plan to lay tubing in sand befor back filling. Is sand ok or is there some thing better for conducting heat?
Paul P

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Originally Posted by cptrdbrd

hello all
I found info on geo thermol heat pump loop length in this group befor. now I am ready to dig the trench now and cant find the info. can any one point me to a therad or a websight to to help me figure how long to make the loop? for waht its worth I am in the northern US, looking at 3 1/2 tons and using pex tubing for the loop.
Another concern I have is we have a lot of rock here so I plan to lay tubing in sand befor back filling. Is sand ok or is there some thing better for conducting heat?
Paul P

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Hi cptrdbrb,You sould find all you need in this doc its a pdf file

http://www.osti.gov/bridge/purl.cove...3/webviewable/

Regards Norm :D

thank youfor the info, but the info is for vertical. I am laying it in a long trench. will this change the info.

You may find something here
http://www.kensaengineering.com/self.../downloads.htm

Brit

hi I am a installer and designer. What information do you need? There are rules of thumb that could work. Soil conductivity will determine the pipe lenght and also the pipe u r using. Sand is OK (not the best) if it is wet but dirt is better. I can find the chart and pdf u some info. my e-mail is richard1900@yahoo.com what is yours? I do not know how to send a pdf throught this forum.

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Originally Posted by richard1900

I do not know how to send a pdf throught this forum.

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Due to the file size restrictions imposed by the Boss, it is better to upload your file to a File Sharing service and then just post the link.

http://www.limewire.com/

http://www.keepandshare.com/htm/free_file_sharing.php

Lots more available also.

i just did a training about this time of units, each ton needs a 250ft loop for vertical installations and they have to be 15 ft from each other, and sand is not the best

Quote:

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Originally Posted by cptrdbrd

hello all
I found info on geo thermol heat pump loop length in this group befor. now I am ready to dig the trench now and cant find the info. can any one point me to a therad or a websight to to help me figure how long to make the loop? for waht its worth I am in the northern US, looking at 3 1/2 tons and using pex tubing for the loop.
Another concern I have is we have a lot of rock here so I plan to lay tubing in sand befor back filling. Is sand ok or is there some thing better for conducting heat?
Paul P

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Obtain a copy of "Design/Data Manual for Closed Loop Ground-Coupled Heat Pump Systems" if you can find one. It covers soil types and conductivities, layout of horizontal systems, etc. It is no longer in print, but it was written by professors at Oklahoma State University. Go to their web site, The International Ground Source Heat Pump Association, at http://www.igshpa.okstate.edu/. They have a number of publications that should be of help.