Hot Geothermal loops!! Can we use our pool to cool??

Discussion in 'Swimming Pools and Hot Tubs' started by homemom, May 6, 2009.

  1. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    One must have FLOW

    to get the BTUH to move.

    GPH plus, Head loss of equipment and loops matched to pipe size equals flow.

    One needs to know FLOW and not just BTUH.

    I think adding pumps will not solve it all.

    One needs to know flow.
  2. homemom

    homemom Member

    *Insulation R45ish *Mech Engineer gave "OK" on duct work (for 5zones)
    (We will add additional coverage for all west windows.)

    "banks of slinky" ?? More info. we have 4ft dirt, 80ft lava, then more dirt. Note: wells will cost $300/hr

    Flow rate is good per good Geo tech. - exchange is probably bad do to voids in the lava - just a guess. So 8 loops could act like 6

    Ok I've been thinking... to cool the loops what would happen if we used the secondary water?? Hook up the COOL secondary water to flow into the loops daily, use the exit water to water the yard, plants & garden? ( Send the rest to the sewer. If loops became quite hot we could see the cost of running it for longer periods of time. What do you think??
  3. Bergy

    Bergy Member Industry Professional Forum Leader

    Desert and water

    Water is a precious resource, especially in the desert. To waste such a resource rather than fixing the problem would be a shame. What about the people who designed this system? If I'm paying someone to design a system to operate properly at design temperatures, it D@^N well better work. I am not a litigious person. I've never been a fan of lawyers but I think I would have one retained, writing nasty letters and demanding results.

    I wish you luck.

  4. Guest

    Guest Guest

    4ft is usable and lava should be (references needed) a better conductor than desert dry soil. So maybe dig down to 4ft, get a nice clean contact with the lava, lay the loops, then cover with a few inches of concrete/soil mix. Ie, bond the loops to the lava.

    It is also possible that with poor soil conductivity, you just are not a good candidate for closed loop geothermal and that some type of evaporative or air source cooling might be best.

    I tend to agree that your system was not well designed.

    Where does your drinking water come from (well or city)?
  5. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    GSHP=ground source heat pump.
    Have you been able to determine wether 200'/ton bore holes are typical in your area? Have you been able to determine wether loops were grouted (properly) during install?
    How many sq' is the house?
    Have you been able to determine wether the load you had done is accurate (I can see a little disparity from one guy to the next, but 3 tons....)?
    The problem I'm having here is that what you have isn't working correctly, so I'd really prefer to solve that problem before moving on to your secondary problem. A properly operating 8 tons might keep you cool 90+% of the time (if load is correct) that could take some of the panic out of the second problem (though obviously it's still not ideal).
    So in my mind, the real question is who can we find to come and troubleshoot and repair your existing system?
  6. homemom

    homemom Member

    A few answers...

    We have city water. 200 ft is common... per ton (I'm just the only one on deep lava)

    Drillers grouted as best they could, but they ran into some large pockets (took 6- 8 weeks to drill 8 holes) had to leave 2 sleeves that could not be removed from the lava.

    I'm not one to talk badly about people but.... the Geo Contractor was a knuckle head. Didn't even use the blueprints to figure the proper tonnage. I hear he is bankrupt. Several people are having trouble with his work - no common sense. Yes, we are 3.5 tons short, plus the bonus & basement are linked - should have been separate...the 3 tons does the 3200 basement and the 800 bonus.

    Secondary water - I agree I hate for it to go to waste, that's why I thought I could run the secondary water through he loops first then use the exit water to water the yard - daily. We have about 1/3 acre to water. I don't know if it would even help - it may be a drop in the bucket. Just a thought. Plumbing is doable.

    House 3100 main floor, 800 over garage, and 3200 basement. :eek:

    Like I said there is one GOOD Geo in town that does commercial buildings. He recommends redoing all ductwork - no zones - doesn't like zones - uses good trunk system - little flex. His helper says keep the zones, better control of temps, not worth redoing all the ductwork and insulation, .... better to add conventional tonnage. They already replumbed the 3 & 5 tons units (was hooked in series - now plumbed parallel)

    Mech. Eng. says short on cooling...redoing the duct will not fix that. Adding 5 ton conventional tonnage will not fix the hot loops, but could give the system a only give it a 6 ton load, instead of the full 8 ton - trying to do 11. Just my opinion. also expensive

    I agree ... two problems....tonnage and cooling....

    So many problems, so little $$ ;)
  7. Guest

    Guest Guest

    I'd guess that you are getting about 6 tons from your 8 ton system. And drawing a lot more power in the process.

    You could add a couple of mini-splits to add capacity.

    The Fujitsu Halcyon 12RLS is amazingly efficient.
  8. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    talk about flow

    I would have gone with low Portland mix to the lava bed.

    Do not spend any money until you look at flow.

    I do get retentive when I See a system that is being ignored about flow.
  9. homemom

    homemom Member

    Go with the FLOW

    Ok... Is "Flow" something I could check? Is this something the Geo Tech would do? What should the flow rate be?

    Had the Geo Tech out here not to long ago- checked for air pockets in the line and added more water and a conditioner - to seal any possible leaks. He said it looked good except it was running hot for May - only running a few weeks.

    Tech was going to bring me a gauge to check pressure on my own - just to keep and eye on things - make sure it was within guidelines. I could ask him to give me specific flow info.

    More notes on the system...
    the 3 ton and 5 ton are NOT separate loops. It is one big loop (yeah I know) - as I understand it the water branches out to all the wells at the same time - more like l l l l l l l hooked together. Not like WWW . Did I explain that OK??

    The "bad" Geo's son-law (who left the business) said he would come back to help with any info we needed, he felt bad for us.. Any questions I could call him with?? We also know who the driller is.

  10. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    In the I/O manual

    There will be either a GPM per ton number and/or a PSIG drop through the heat exchanger coil. That will give you the amount of flow required through the machines. The PSIG drop is easy to read with a pressure gauge on each side of the unit. Flow meters are available. You need to know how many feet of what type of pipe make up the loops. You also will need to know how the loops are plumbed. There are tables for calculating the total resistance to flow, (called Head) and tables for any fittings.

    Add all that up and compare the total to the pump curve from the manufacturer to make sure the pump can do the work.

    It comes to mind that if the multiple units share the loop field and the piping is not correct the water in the system will take the shortest and/or easiest route, causing the over heating.
  11. Guest

    Guest Guest

    Water will take all available paths in proportion to the resistance.

    But it would be interesting to know if each of your vertical loops has the same return temperature. Quite possibly it could be better balanced.
  12. homemom

    homemom Member


    I see your point, I'll look into it, get a copy of the loop layout and such... but it may take a few weeks to get the actual flow rate.

    Downside - 4 loops are under the driveway 4 are accessible. I'm not sure if we could correct any issues we did find.... Would we need to tear up our driveway? The "Cure" maybe more expensive than keeping the "disease".

    Thanks for the info.
  13. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I would

    first look at how the systems are plumbed to the loops.

    Are they piped with swing check valves to prevent one machine pumping into another instead of the main loops.

    If I were to design a system with multiple units on a single loop system I might use a primary secondary configuration. Imagine a large circle, the primary loop, with its own pump, sized to the head loss and GPM requirement of the loop. Now add a half circle for each machine, with the half circle equipped with a small pump to feed the machine and near machine piping. The trick to this system is that the ends of the half circles must be very close to each other on the primary loop. No farther apart than 4 pipe diameters of the primary loop.

    This idea would allow for noticing any true failure of the main loop field. It will also maximize heat transfer in the main loop. Each secondary loop transfers what it needs in BTUH with its own pump. The purists here will whine about the extra pumps, but they will use less energy than a conventional a/c system.

    I would also spec the use of ECM powered pumps controlled with delta T or P. There are a few pictures of what I mean in the gallery area of my profile.

    Is it possible to post a picture or two of the near machine piping or the area piping where the individual systems meet the loop field piping?
  14. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

  15. Guest

    Guest Guest

    My understanding is that you want loops in parallel with each other but check that the flow rates are all high enough to not get laminar flow.

    Multiple heat pumps also in parallel but with valves to prevent flow when not needed.
  16. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I have

    seen lots of poorly done parralle systems. P/S is sure to work and in Homemom's case could help solve her lack of cooling issues by fine tuning the zoning system.
  17. homemom

    homemom Member

    Pics are in my profile - sorry some are sideways. :)

    Thanks for the TECH Reading. "Everything you want to know about Geo Thermal" I have my homework cut out for me, it's better than Trigonometry.

    I may give you a call, let me review the manual, and get more tech specs.

    We live 2hrs north of Las Vegas NV

    Thanks again all !!
  18. homemom

    homemom Member

    Nice - this just might solve the other problem I have. We built a COLD storage unit in our basement - The Geo Contractor ran the HOT loops through the room :mad: So my cold storage is now the warmest room in the house.

    Since it is a cold storage room, very well insulated, I have only a small gap in the floor trusses that could exit to the garage. This unit might work.
  19. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Re: There is no reason

    You can't pipe two heat pumps in series but the flow rate must be suitable for combined tonnage. IOW if you have 8 combined tons and a properly sized loop field you are okay as long as you have 24ish gpm.
  20. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    The pictures are not up yet.

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