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Questions about a closed loop Geo System to cool only

Last Post 08 Apr 2008 06:19 PM by geodean. 13 Replies.

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sled4fun

New Member

Posts:27

03 Mar 2008 02:52 PM
I have been thinking of using loops in the ground with a large water to air exchanger inline with my a/c unit & ducting. Questions: 1. If I used my existing duct work to circulate the air and a small water pump to circulate the water through the loop. Would it keep a tight single level 2500SF S.I.P. home cool? (75 degrees or so on a 110 degree day) or at least allow the existing a/c to work easier. 2. I live on top of a hill and have plenty of north side shaded ground to use for the trenches? 3. About what depth and length of loops would I need?

Palace Geothermal User is Offline

Veteran Member

Posts:1609

03 Mar 2008 03:26 PM
This sounds like a system with out a heat pump. So if the water coming out of the ground is 60° and you run it though a coil and blow 75° air across the coil how cool will the air be? 70° if you are lucky. Can you cool your house with 70° air? Depends on how much heat gain you have. I don't see this a viable cooling method. It might lessen the load on your A/C unit, but paying back the cost of putting all that pipe in the ground will be close to forever.

Dewayne Dean <br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system

tuffluckdriller User is Offline

Advanced Member

Posts:630

04 Mar 2008 12:47 AM
Actually, that all depends on the cfm of air, and surface area of coil. It could theoretically work, but there are design issues that need to be taken care of. It's not necessarily an easy setup, but it could work.

Clark Timothy ([email protected])<br>Geothermal Heat Pumps: Heating and Cooling that's Dirt Cheap!<br>www.pinksgeothermal.com

Klorinth

New Member

Posts:33

07 Mar 2008 09:56 AM
Tuffluckdriller, You're talking about a fairly large coil aren't you? OK a LARGE coil. Cost? It just doesn't seem to be worth the expense of installation and running. Why not go with something like this? http://www.mb-soft.com/solar/intake.html I agree this site is a little questionable. They really try to sell things, tweak and twist the numbers, use some good jargon... but, the basic idea is sound. Research has actually been done, in a true scientific manner, and the numbers are fairly good. All you are doing is preconditioning the intake air prior to having it cooled (or heated) by a traditional system. Makes that system more efficient. The cost is in the trenching and laying of pipes, no significant change to your current system. Most will consider this a little to novel, but what the hell. ps. If you scroll to near the bottom of the webpage there is a section where they talk about the problems of condensation in the tubes. Given the hilltop setting of your house, this would not be an issue because the pipes would be running down hill. As long as there is a built in drainage point(?French Drain?) at the lowest point. There is also a link to an alternate system which is similar to what is being discussed here. [/quote][/quote]

Palace Geothermal User is Offline

Veteran Member

Posts:1609

07 Mar 2008 07:51 PM
I went to the webiste in the above post. No way was I going to read all of that nonsense. I did get a chuckle out of this part " We have a gripe! A large number of people do not seem familiar with the story about not looking a gift horse in the mouth! (When someone GIVES you a horse, it is not very polite to immediately attempt to determine the quality and health of the horse!) This presentation is a GIFT! We didn't try to SELL you anything, or even try to FORCE you to make any decision! This information is LOOOOOONG because we tried to provide sufficient information and logic so that you might get a basic understanding of the concepts behind it, and that we attempted to include a reasonable amount of information regarding actually installing it. We get a lot of notes that complain about how long this is. Sounds somewhat like Gift Horse to us! But a large number of people INSIST that we provide the names and addresses and phones of people who have installed such systems! We feel that is incredibly offensive! How dare people insist on bothering people (WITHOUT then being expected to pay any money for any product!) just because they happen to not understand the value of something? Hey, go ask for the pedigree papers on that Gift Horse! Other people seem amazed that these web-pages do not include testimonials of people who installed the system. Again, if we were trying to SELL such a system, that would make complete sense, in trying to convince you to want to give money to us! But since that is not the case, we really see no reason at all to feel any need to provide such testimonials. Do you really believe all those TV ads where people claimed to have lost 80 pounds in three weeks while eating everything they like? If you choose to find no value in these pages, fine! You are free to do that. If you are not sure, you are free to hire some local Civil Engineer or Thermodynamicist to examine these pages to tell you whether or not there is any value here. But we have pretty much gotten tired of responding to Gift Horse e-mails, and probably will never again respond to such notes!"

Dewayne Dean <br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system

Palace Geothermal User is Offline

Veteran Member

Posts:1609

07 Mar 2008 10:08 PM
Posted By Klorinth on 03/07/2008 9:56 AM All you are doing is preconditioning the intake air prior to having it cooled (or heated) by a traditional system. Makes that system more efficient. I don't see how this can help heat a house at all. If you take 70° air out of your house, run it through 55° ground and then bring it back into the house, the air is coming back colder than when it went out. The whole idea just doesn't seem like it is practical. Just my opinion.

Dewayne Dean <br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system

Alton

Veteran Member

Posts:2164

07 Mar 2008 11:05 PM
I read the whole article that Klorinth mentioned above. Since I have used cooling tubes in one solar energy home in the early eighties, I might be interested in this system. Does anyone see any reason why it will not work in mid-east Alabama?

Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period . 334 826-3979

Klorinth

New Member

Posts:33

07 Mar 2008 11:24 PM
Geodean, I did laugh at multiple points as well. I totally agree with you that too much of that long winded page is jargon meant to confuse and warp your perception, etc. I also agree with you that if you try to use it in the way you mentioned it most certainly would not work. In fact it would do the opposite. But if you are using it as your fresh air intake then it is a different matter. That is the main use I see.

Palace Geothermal User is Offline

Veteran Member

Posts:1609

08 Mar 2008 10:37 AM
I can see how it would be of benefit for fresh air intake. But this product will do the same thing. Alton, what was your experience with cooling tubes? My intuition tells me that this will not work very well. But experience always beats intuition. I am like the others who have read the article and then questions the veractiy. Tell me some one who has done this and it has worked. I was ready to call this a hoax and then I did a Google Search and there is a fair amount of info on the web. Maybe there is some benefit, but I still say it has to be minimal.

Dewayne Dean <br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system

Alton

Veteran Member

Posts:2164

08 Mar 2008 11:39 AM
Before I did the superinsulated active/passive solar residence in Winnsboro, SC (near Columbia) I was quite familar with earth cooling tubes being used in Iowa with hog barns. Instead of using corrugated plastic pipe that could trap condensate in the grooves, we used concrete culvert pipe. We saved quite a bit of money by using pipe that did not measure up to highway standards. We buried the pipe about 8' deep and sloped it to grade so the condensate would drain. We sealed the pipe joints and brought the pipe up through the concrete floor. Since the home did not call for airconditioning, our plan called for an exhaust fan mounted in the attic to pull air through the pipe. Although we did permanent instrumentation on the active solar system, we did not attempt to measure the cooling from the earth cooling tube. I supposed this system worked reasonably well since I never heard any complaints. I know this is not a ringing endorsement of earth cooling tubes. My guess is that not enough moisture was removed from the incomming air. As we know, latent heat in mositure laden air can be uncomfortable. I believe this system would work much better in arid climates.

Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period . 334 826-3979

Klorinth

New Member

Posts:33

08 Mar 2008 09:01 PM
All of the research that I have done points towards it being more effective in desert type climates. Part of this may simply be do to that fact that not much has been done in any other climates. Now that being said... I don't think it would be as effective in a very humid climate. Which is my issue here. The upside for me is that the humidity here is only for a limited period in the summers. What appeals to me is that it is meant to be passive or almost passive. The only energy input post installation would be with the ventilation fan already being used in the home. That means nothing extra added to the bills or environmental footprint, but a possible gain. I understand the issue inherent in this idea, but it does have potential in the right situation. Here are two papers that may be interesting: http://www.builditsolar.com/Projects/Cooling/Earth%20Tubes2003-01-07GirjaSharan.pdf http://www.ivt.ntnu.no/bat/bm/buildphys/proceedings/67_Staahl.pdf Also Google "Passivhaus" As long all of this causes some more thought then I am content with that. I have no desire to change anyones thinking. [/quote]

sled4fun

New Member

Posts:27

10 Mar 2008 11:03 AM
I was thinking of about 1000' ft of cooling tube and a water to air finned exchanger of about 24" x 24" by 18" thick. The exchanger will be installed and sealed in a 36x36 cieling crawlspace that joins one end of the house to the other and will have a small fan constantly circultaing the air around and through the house. I can resize the exchanger to what ever I need. What size & type piping for the ground loop?

sled4fun

New Member

Posts:27

08 Apr 2008 06:12 PM
Found this site. It is what I was thinking of. http://mb-soft.com/solar/alternwa.htm The page talks about a water based system. If you scroll to the bottom it links to the original cooling tube system.

Palace Geothermal User is Offline

Veteran Member

Posts:1609

08 Apr 2008 06:19 PM
Interesting idea, let us know if it works.

Dewayne Dean <br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system