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

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

  1. homemom

    homemom Member

    a little background... We have climatemaster geothermal system- loops were at 100-130 mid-summer last year and they shut down several times. :eek: (Great units- poor geo-contractor)

    We live in temps close to Las Vegas (5 degrees cooler). We found out that we are 3-4 tons short on cooling for our home. I am looking for options. Drilling more wells is not possible. But we are thinking about a pool - is it possible (and effective) to use the pool to cool the loops?? Since our weather is very warm in the summer would there be enough exchange?? is it $$$ worth it?

    Currently we are planning to "piggy back" a 5 ton conventional system to take the burden of the main floor off the geothermal so when it shuts down we can still live in the house. If you have any input it would be GREATLY appreciated. :) Thanks!

    "If money will solve your problems, then you really don't have big problems." :rolleyes:
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Yes, theoretically, it is possible to use the pool to cool the loops. You will be relying on evapotranspiration to do most of the work in this regards, so leaving the pool cover off becomes beneficial. There is also some issues with plumbing that will have to be sorted out.
  3. homemom

    homemom Member

    Are there other ways to cool loops? Or is it just best to reduce usage of the units?

    Should I leave the geo alone, and rely on the 5 ton conventional unit to supplement the Geo?? Possibly, scrap the whole geo thing... and go total conventional for the summer months?

    It's May and my loops are at 90 degrees by evening - it's only mildly warm outside now. I can't take another summer with my kitchen at 82 degrees.

    One more questions...... When are loops too hot ?? I know the units will shut off around 125-130, but is best to shut it down at lower temps to avoid damaging the climatemaster units?

    Any whole or part answers are welcome. Thanks -
  4. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I've been mulling this over for use in North Florida. Las Vegas, though hotter, has much lower dewpoints (humidity) than we have. Right now LV is at a dewpoint of 37 where ours is in the 60s, a huge difference.

    That means that evaporative cooling would work really well. Several other thoughts:

    1) System that is badly underlooped may not be undersized - as loop temp rises actual tonnage falls to well below nominal tonnage.

    2) Every pound of evaporated water such as from a pool absorbs almost 1000 Btus, but you need to consider both the cost of makeup water and the possibility of the water left behind becoming progressively 'harder', that is, concentrated with minerals.

    3) Cost of pool chemicals and effect of chemicals on heat exchangers - may need intermediate heat exchanger, adding cost and complexity.

    This could work, but designer and installer needs to be sharp.
  5. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Cost of water could have a huge impact on your decision to cover or not to cover pool if you do this. It is certainly doable. You really need to find a talented local guy to help you with your problems in general- determine the system short comings before you spend money on anything else. Climatemaster is finally starting to list local dealers on their web site you might look there first and check the IGSHPA for trained loop techs in your area...I agree with engineer that until you get the EWT down you can't call the system undersized. Has anyone done a manual J load?
    High temps are not completely without consequence to your heat pump, but the lock out you are experiencing will protect it. I would suggest that constantly taxing an inexpensive limit switch will eventually cause it (the switch) to fail, though no immediate, expensive harm will befall the equipment.
    Food for thought; an undersized system with an adequate loop field should be unable to transfer too much heat to the field/ make the EWT too high. In other words, it should be able to continue to operate (though not reach your desired set point) indefinately.
    Good Luck,
  6. Guest

    Guest Guest

    You have vertical loops?

    I would consider a pool - look for surface area, no cover, maximize wind.
  7. kmckinley

    kmckinley New Member

    My guess is that initially the pool will work OK but it will quickly become a heat reservoir and system efficiency will erode.

    Much like dumping cold return water back into the same well here in the Northeast when heating with an open loop system. Sounds good in theory but does not work.

  8. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    It will. The pool isn't a closed system. Like any surface water body, the greater the delta T, the greater the evapotranspiration, the greater the heat loss. Granted you could fully evaporate your pool, but this is where some design foresight is required.
  9. geo fan

    geo fan Member Forum Leader

    What you describe could work
    how hot does the pool get now?
    Is the system currently zoned
    Is there room to improve insulation / infiltration
    Has the duct work had a good check for leaks , if its in the attic moving it to the living space can have a huge effect .
    In short there are usually more then a few things that you can do , that would be money well spent regardless if it was sufficient or not like low e window film , it will help keep the house cooler if that doesn't cut it double your attic insulation , if that still doesn't do it and moving ducts and zoning are out of the question pop in a mr slim ductless in the most used room . just a opinion . I would hate to see you do it when you likely dont need or want much more heat in your pool only to find out your still short
  10. moondawg

    moondawg Member

    Wait. Do you ALREADY have a pool, or are you just considering installing a pool to absorb the heat from your home? there may be more efficient ways to evaporate water in order to cool your loops.

    Can you explain why drilling more loop is not an option? (there are some very crafty drillers out there who can drill just about anywhere.... you may not have asked the right question to the right people)
  11. homemom

    homemom Member

    I'll try to answer a few questions..... Thanks for all the input.

    We are thinking of adding a pool....we do not have one yet.

    Our biggest problem is hot loops...Currently at 80-90 (will be at 100-130 by mid-summer and will most likely shut down again.)

    Yes, we did pay an engineer to do a heat load calc. on our home. We ARE short 3 1/2 tons - minimum. Main floor load is 5 tons- min.

    Note: drilling is not $$ possible we are on lava/holes - drilling is NOW $300/hr. took 2 weeks to drill 1st hole :eek: - driller will not come back - can't blame him he lost money on the job- nice guy he honored his bid.)

    Our current options that we are aware of are;
    1- add conventional 5 ton unit to supplement geo- in summer months. (completely separate ducting with thermostat)
    2- cool loops
    a - use pool to cool loops (we live near LasVegas)
    b ???

    System is Evolution- zoned (love the zones!) Duct work is only OK, lots of flextube, a few hard turns. No main trunk. Had a few people take a look at it, "it's what you see alot of now".

    If you have any great ideas they would surely be welcome. We have only one local geo guy that is good. He only does commercial (and kindly helps out the people who used the other geo-contractor). I don't know if he has any experience using a pool to cool the loops. I may have another person to work with who sometimes travels to this area - He's good also.

    Do I have other options?

  12. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    okay, you can't make a system that's too small get the job done by over cooling the loops. Miles of loop will not significantly improve it's capacity (though undersized loops can derate it).
    You really have more than one question here.
    1) how to get the most out of the equipment you have
    2) how to meet the actual load
    That's how I would approach perspective contractors. See who has the best idea.
    As was mentioned, there are more effective ways to augment your loopfield than a swimming pool.
    Anywhere you can fit a pool and the equipment to dig it, I can fit some loops and the equipment to dig it.
    Good luck,
  13. homemom

    homemom Member

    Good info.... so...If the Geo is hot do to overload- it never gets a break, best option is to add tonnage?
  14. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    I don't think your loops are hot due to overload, I think they are hot because your installer was a dumb:):):) (I'm sort of kidding). If the field were designed for the load (size of the heat pump), it shouldn't get to 120* EWT. If your unit is a 4 ton for instance, it doesn't matter if there's 10 tons of load in the house, the unit can still only put 4 tons into the loops.
    So I'm saying your loop system is too small..... and.... you may have to add tonnage.
    Again, these are seperate problems.
  15. Guest

    Guest Guest

    Agreed. If your loops are too hot, the definitely wrong solution is to simply add GSHP tonnage.

    When loops get too hot, they dry out the soil and reduce thermal conductivity. Then the ground shrinks and pulls aways from the tubes. All of this makes the problem far worse.
  16. Bergy

    Bergy Member Industry Professional Forum Leader

    Yea, but it's a DRY heat!

    Have you considered a cooling tower?

  17. homemom

    homemom Member

    Dry heat. :D

    Hummm... So remembering there is only so much $$ in the pot. Where do I get my best bang for my buck? Do I have to solve both problems??(I do see your point.) Each would be expensive.

    If the geo runs (I think) as it should during the winter months. We need to solve the summer situation. If cooling the loops will not really net us the cooling capacity needed (as mentioned above) what is and what will a cooling tower provide?

    If we need 11tons and we have 8 tons will a cooling tower makeup the difference? Or do I still need to add conventional tonnage?

    What would and be cost effective??

    What is GSHP? (house wife, not contractor- although I've about earned the title.)

    Well info: 8 holes at 200ft (80ft is lava/holes) buried 2 ft under surface-should have been 4 or 5 feet. grrrrrrr

    PS....just thinking outside the box -- We have almost unlimited cheap "black water" ....could it be used to cool the loops?

    Thanks again... More info- the better to make a decision with..
  18. geo fan

    geo fan Member Forum Leader

    Im sticking to my guns here
    money best spent add loop ( if you can dig for a pool you can dig plenty deep for a couple banks of slinky )
    Lower the load , seems you have brought in allot of professionals ( some more then others ) and 3 tons is a long way to go couldn't hurt to bring in an insulation consult to see if they think they can drop the load by that much, or contact that engineer to see if his calcs show enough weak spots to make up the necessary difference , you may be surprised. and definitely effeciency wise a better option then adding tonnage .
  19. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    You must Know


    If there is air, no flow.

    If there is anything that allows the water to be lazy, no flow.

    You need a hydronics person.
  20. Guest

    Guest Guest


    add more underground loop (perhaps with a soaker hose)

    add a loop to outside air heat exchanger to your current system to improve the ground loop performance (when loop temps are more than outside air temp).

    put in a pool

    add a conventional air source air conditioner

    Sounds like the first 3 still require adding another GSHP (ground source heat pump)

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