Help with a DIY verticle slinky Geo Install

Discussion in 'Vertical and Horizontal Loops' started by Links56, Feb 27, 2019.

  1. Links56

    Links56 New Member

    I'm planning on installing my own geo system at my home, I am an electrician by trade but my brother does HVAC and I have been involved with him on installing several systems and have gotten lots of help from you guys on different things in the past. I have some questions that may seem like simple stuff but I have only been involved with the sizing of the ground loop and calculations a couple times.

    Some background info, I have a 1750 sq foot brick house, it is an old farm house so it has old wood leaky windows and not much insulation in the attic. It also has a identical basement that is a separate living space. I plan on fixing these issues as money allows but i have all the equipment and materials to install a ground loop, I have thousands of feet of 3/4 poly and a fusion machine, several geo pumps, flush cart, backhoe, excavator, etc. So id like to get the loop in this year if possible just so its done and then Ill slowly build the rest of the system.

    I have a 1000 foot spot that I can dig a vertical trench along the treeline so its shaded my soil is pretty sandy but the ground water level is only 15-20 foot down during the dry times of the year but it is a spot that gets saturated with water heavily . I also am installing 400foot of conduit in the same trench to get underground power to my pool. Get 2 birds with 1 stone.

    Would it be possible to have one long vertical slinky with a valve box under the frost line so I could tie in a loop that would run a loop around the base of my 37,000gal swimming pool, during summer I could tie the loop in and use the pool to absorb the heat and in the winter I would switch the valves so the pool loop isn't tied in to the ground loop. I cant widen out until after the pool which is about 700 feet from the house. I estimate I would need 5-6 tons of cooling and 60-80k btus for heating. The soil is sandy so I was figuring 800 feet per ton. I'm concerned about the pressure being too high and could you put a manifold 700 feet from the house and run several loops at that point? I'm located in the midwest on the Illinois Iowa quad city area boarder 1.5 miles from the Mississippi River. I have a 5 ton coil in my propane furnace currently and I would like to use the compressor from the condensing unit and install a reversing valve and run the Freon through a copper coil submersed in an insulated 55gal plastic barrel that would have my ground loop water circulating through the barrel. I think doing it this way would allow me to add other heat sources later if I were to get ambitious.

    Please keep in mind that I'm not familiar with the calculating part of things so some of my numbers might be way off which is why I'm posting this. What do I have wrong? and How would you recommend I do this? Thanks in advance for your time and advice.
  2. nc73

    nc73 Member Forum Leader

    Follow the KISS principal.
  3. Links56

    Links56 New Member

    I guess my main concern is recirc pump head pressure. I don't want my recirculation pump for the ground loop working hard all the time running up electricity bill.
  4. ChrisJ

    ChrisJ Active Member Forum Leader

    700' is a long way to go to use the pool!

    I am not a pro. I think you have to do it with large pipes out to a reverse return manifold, then 5-6 slinkies in trenches 10' apart.
  5. Links56

    Links56 New Member

    Yeah I know 700 foot is a long way but even if the pool wasn't there is still have to go almost as far as there is only 4-5' between the house and the tree line the the same width between the back of a shed/garage to the tree line. I wasn't going that route specifically to use the pool but since I have to go by there anyway and even when it's 100 plus that pool is only 80 degrees at most and it would be a useful way to heat it a couple degrees and take some load off the ground loops in the summer.

    So by bigger pipes to the manifold are we talking 1" or 1.5" to a 2.5" manifold roughly? And what depth should I put the loops at? Thanks so much for your input I appreciate it.
  6. ChrisJ

    ChrisJ Active Member Forum Leader

    Again I'm not a pro.

    I think using 1.5" or 2" out to where the trenches are, then down size for the reverse return manifold

    My brother in law uses a air to water heat pump designed for pools, much easier then what your thinking about. The ground loop probably won't get warm enough to heat the pool, if it did the heat pump would not operate as efficiently using 100*F fluid.
  7. Links56

    Links56 New Member

    Ahh that's a good idea for a efficient pool heater. My in-laws are all elderly so they are always freezing in the pool. I know the ground loop to the pool thing wouldn't even raise it a degree or two probably. I also thought about a wood fired boiler to heat the pool also.

    So I guess then how deep do I put the loops since I have sandy soil would deeper be better? I would think having the slinky deep enough to be in the water table would be best for heat transfer? Am I okay to bury it 14 plus ft deep or is there some negative reason im missing. I appreciate the advice and it doesn't matter if your a pro or not you know more than me and are willing to share your knowledge with me and I appreciate that. If it doesn't work I'll dig the manifold back up and add more loops.
    Thanks again.
  8. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    You are setting yourself up for failure, you are not in the mindset of cost-effectiveness versus reliable performance.

    What your are talking about is complex and expensive to do, and will not give you a good performance. Why are you trying to reinvent the wheel?
  9. Links56

    Links56 New Member

    Well how would you do it? I'm here for advice, I am a disabled veteran with limited income I live in a state where my taxes have tripled in the last 5 years, I'm trying to use the materials and equipment I have already to reduce my heating and cooling bill. Then I could use that money savings to slowly insulate and change Windows. If I had a bunch of insulation and Windows id be putting them in instead to Start out with. The only money I'll have to spend is for the reversing valve and some fuel for the equipment. The rest is time as long as I get the ground loop installed properly then If my homemade heat pump is a big failure then I'll have to do something else. Unless you happen to know where I can get a dirt cheap heat pump. I Also have the outdoor woodstove option for heat as I have built several from scratch for people and they have operated fine for years but once again I don't have the materials to build a boiler for myself right now I do have the water to air heat exchager but thats it.

    Seriously though that's why I'm here for your advice and guidance, I appreciate input negative or positive. What wpuld you do if you were in my shoes? If I can't cut costs somehow I don't think I can afford to live in my home if they keep jacking up property taxes from everyone fleeing the state. Right now I'm going through 2000 gal of l.p. in a winter and I have to cut that back somehow. Thanks for the help.
  10. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    It is not the money I was commenting about, it was that you were all over with your design and what you wanted to do.

    1) Reduce you load. weather strip and insulate.
    2) Figure out what your heating load is.
    3) put in a horizontal loopfield, 7 circuits with slinky loops 600 ft long, so your pressure drop is reasonable.
    4) put a heat pump in.

    If you are on a as much of a budget as you say, don't worry about pool heat, no valve box, no under the frostline valve box, don't go 700 ft from the house.

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