Page 4 of 6 FirstFirst 123456 LastLast
Results 40 to 52 of 75
  1. #40
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,070
    [QUOTE=Gross;11796162]
    Quote Originally Posted by ga-hvac-tech View Post

    Also; seems to me if we are transferring heat or cold to soil... it does not matter the medium to carry the heat... what matters is enough soil contact to effectively dissipate the heat/cold. If this is true (suggesting, not stating), then it seems irrelevant which medium is used to carry the heat... what does seem important is enough ground to absorb the heat applied.

    QUOTE]

    Thats not completely true and here is why. water, or antifreeze, doesnt transfer heat rapidly. HDPE is an insulator (R-.6 or .8) so its not the best at getting rid of the heat in the first place...now when your ground temp raises, the heat transfer rate stays the same. as the ground warms, so does the water....since the heat goes from refrigerant to copper to plastic to water to plastic to earth, it imperative that you get the absolute best transfer each time. when the ground warms up it REALLY shows on your water temperatures.
    DX on the otherhand only goes from refrigerant to copper to earth...and since copper is a conductor, not an insulator, it doesnt have to over come the heat sink that is the HDPE and the water.

    Even if the earth was 90 degrees, a DX system would work fine....would you mind 90 degree liquid temps?
    So what you are saying is:

    Since DX runs refrigerant through the loop... the temps are wider and as such X-fer works over a wider soil temp?
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  2. #41
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,070
    Quote Originally Posted by Gross View Post
    same as any well...drill until its clean...

    http://www.energysavers.gov/your_hom.../mytopic=12650
    that shows you a basic idea of different kinds of water source geo's. Water you do for a field in a body of water is you coil up the hdpe, just like a horizontal field, push it out into the body of water and as you fill it with coolant, it becomes heavy and sinks...you can put weights on it as well.
    Interesting link.

    Do folks bury ground horizontal loops with the coil method... had not read much about that.

    Most of what I hear in my area: Contractors do wells. Generally one 150-200' deep well per ton. Problem is... it requires lots of permitting (multiple agencies have to approve it) and is expensive. Kinda leaves geo not cost effective when one has to go through all that.
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  3. #42
    Join Date
    Aug 2011
    Location
    Eastern Shore, MD
    Posts
    798
    Quote Originally Posted by ga-hvac-tech View Post
    Interesting link.

    Do folks bury ground horizontal loops with the coil method... had not read much about that.
    they do BUT the ground temp is much colder in the winter and warmer in the summer at shallow depths... some do it to get around well permitting

  4. #43
    Join Date
    Aug 2011
    Location
    Eastern Shore, MD
    Posts
    798
    [QUOTE=ga-hvac-tech;11796192]
    Quote Originally Posted by Gross View Post

    So what you are saying is:

    Since DX runs refrigerant through the loop... the temps are wider and as such X-fer works over a wider soil temp?
    yes and no. you dont constantly have heated water running through the comparitively short wells with DX and they dont store heat (or lack of). So while the ground will heat up, its ok bc the superior heat transfer can deal with it. Its designed so the rate of heat dispersion (sp?) of the earth is equal or greater than the rate of input.

  5. #44
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,070
    [QUOTE=Gross;11796272]
    Quote Originally Posted by ga-hvac-tech View Post

    yes and no. you dont constantly have heated water running through the comparitively short wells with DX and they dont store heat (or lack of). So while the ground will heat up, its ok bc the superior heat transfer can deal with it. Its designed so the rate of heat dispersion (sp?) of the earth is equal or greater than the rate of input.
    THX for the answer on the other post.

    Seems to me if one shut off the water pump between cycles of the geo unit... and made the loop large enough... one would over-come this issue.

    Thoughts?
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  6. #45
    Join Date
    Aug 2011
    Location
    Eastern Shore, MD
    Posts
    798
    [QUOTE=ga-hvac-tech;11796372]
    Quote Originally Posted by Gross View Post

    THX for the answer on the other post.

    Seems to me if one shut off the water pump between cycles of the geo unit... and made the loop large enough... one would over-come this issue.

    Thoughts?
    again, sort of. the pumps usually do shut off between cycles but hot moves to cold...so the water temp is still evenly dispersed...

    bigger field means a bigger pump which means more energy draw...

    This is why no watersource mfr's put the pump inside the cabinet...it would hurt their EERs and COPs too much.

  7. #46
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,070
    [QUOTE=Gross;11796412]
    Quote Originally Posted by ga-hvac-tech View Post

    again, sort of. the pumps usually do shut off between cycles but hot moves to cold...so the water temp is still evenly dispersed...

    bigger field means a bigger pump which means more energy draw...

    This is why no watersource mfr's put the pump inside the cabinet...it would hurt their EERs and COPs too much.
    THX 'Gross' (screen name) for the input, it is much appreciated.

    I have some things I need to do today... may get back to you this evening.

    Can you send along a PM with a few links I can read for more education? I think the mods would take them down from a public thread. THX!

    GA
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  8. #47
    Join Date
    Aug 2009
    Location
    Beatrice, NE
    Posts
    2,068
    [QUOTE=ga-hvac-tech;11796032]JP...

    I was talking to someone a week or so ago... they said something about the ground getting heat-soaked or cold soaked. What that means is; after years, the efficiency just goes down. I can understand this, makes good sense.

    Any of the geo contractors know if wells get heat soaked?

    I have never heard of heat/cold soaked before. I have some systems out that are 20+ yrs and had no problem. I even have a 3 ton system on a 2.5 ton loop that is working fine, it is also over 20 yrs old. In this area we do 200' wells, around 75' we hit some kind of water, may not be good enough for drinking but it still makes a good heat transfer when the end of a loop is hanging in water. On the newer systems we add an extra loop which doesn't add much cost but keeps loop temps more stable.

    I too am looking at building a house in a few yrs with geo and solar mix so I find these threads very interesting.

  9. #48
    Join Date
    Jun 2008
    Location
    Madison, WI
    Posts
    33
    Quote Originally Posted by Gross View Post
    Ok well you're just plain wrong and uneducated on that. I suggest you research DX geothermal before makIng more assumptions.
    I know DX geothermal exists and have been used and in theory should perform better. But because someone installed them in the 1970's and got away with it doesn't make them legal today. At least where I live they are not legal.

    Even if they were legal, would you install thousands of feet of refrigerant pipe in a building when it is not accessible and you hope there never will be a leak? Why would you do that in the ground when in addition there is a chance to break the pipe when installing, assuming it is some rigid pipe. And who pays for thousands of pounds of refrigerant?

    I'm not saying they are not a good idea nor hat they are not allowed anywhere. I'm just pointing out some issues they will introduce. and the fact that everybody (besides some you may know) uses water/glycol should tell that I'm not the only one sharing that concern.

  10. #49
    Join Date
    Aug 2011
    Location
    Eastern Shore, MD
    Posts
    798
    Quote Originally Posted by kaleun View Post
    I know DX geothermal exists and have been used and in theory should perform better. But because someone installed them in the 1970's and got away with it doesn't make them legal today. At least where I live they are not legal.

    Even if they were legal, would you install thousands of feet of refrigerant pipe in a building when it is not accessible and you hope there never will be a leak? Why would you do that in the ground when in addition there is a chance to break the pipe when installing, assuming it is some rigid pipe. And who pays for thousands of pounds of refrigerant?

    I'm not saying they are not a good idea nor hat they are not allowed anywhere. I'm just pointing out some issues they will introduce. and the fact that everybody (besides some you may know) uses water/glycol should tell that I'm not the only one sharing that concern.
    again, youre ignorant to what youre talking about. I, as well as other members of this site, install them currently. I put in two last week. There isn't thousands of feet of pipe or thousands of pounds of refrigerant. Its more like 10-25 lbs, depending on the system. Youre passing judgement on something you obviously know nothing about. As far as breaking a pipe, who pays for the well pipe to be replaced when a hdpe pipe breaks?

  11. #50
    Join Date
    Jun 2008
    Location
    Madison, WI
    Posts
    33
    Quote Originally Posted by jpsmith1cm View Post
    Could you elaborate on the highlighted part above, please?


    I am looking into a geo system for my own home and a horizontal system is the way I've been leaning.
    A horizontal system is only a few deep in the ground. In winter it cools down quickly since no heat will travel to it from above. you will have large dT between summer/winter. If in winter you have 32F water instead of 50F water your heatpump works much harder using more energy and wearing more. You also can get below the HP rated temperature. In addition you need a lot of space as soon as you apply it to more than a home. It is cheaper than vertical well, but the fact that almost everyone bites the bullet and pays for vertical wells should tell you

    We own one of the horizontal systems. Beside the engineers making many mistakes, the inherent disadvantages of horizontal made it so much worse.

  12. #51
    Join Date
    Jun 2008
    Location
    Madison, WI
    Posts
    33
    Quote Originally Posted by ga-hvac-tech View Post
    I can understand what you say... yet how does one keep an open loop clean (stuff sucked up)?

    How do closed loops work when placed in a flowing stream or lake or river?

    BTW: THX for your input!
    Unless I misunderstand, a closed loop system would be placing a HX in the pond or stream. The loop from HX to HP is closed, the stream flowing around it would be open.

  13. #52
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,574
    Quote Originally Posted by kaleun View Post
    A horizontal system is only a few deep in the ground. In winter it cools down quickly since no heat will travel to it from above. you will have large dT between summer/winter. If in winter you have 32F water instead of 50F water your heatpump works much harder using more energy and wearing more. You also can get below the HP rated temperature. In addition you need a lot of space as soon as you apply it to more than a home. It is cheaper than vertical well, but the fact that almost everyone bites the bullet and pays for vertical wells should tell you

    We own one of the horizontal systems. Beside the engineers making many mistakes, the inherent disadvantages of horizontal made it so much worse.
    I thought that was going to be the angle you took.

    So, vertical wells are the 'only' way to go, then? No way to make a hoizontal field work by depth or sizing?

Page 4 of 6 FirstFirst 123456 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event