Hybrid loop

Discussion in 'Surface Water Loops' started by canuk, Oct 17, 2011.

  1. canuk

    canuk New Member

    Hello everyone. I thought I would share my installation in case anyone was thinking a pond loop couldn't be used in conjunction with a horizontal loop. I've got a 5 ton furnace in a 2000 sqft bungalow with the same sized walkout basement. The house is 35 years old with R12 insulation. My installer used six 600ft loops for the furnace. Four are in two 300ft horizontal trenches, the other two loops are in a 1/2 acre spring fed pond, 7.5ft deep. We ran the loops in the pond in the same configuration as the trench, parallel runs, 300ft out. We tied the tubing to T bar to keep them parallel, using enough T bar so the loop would barely float when empty, which quickly sank when filled. The system has run for two winters with no problems at all. (I'm in Ontario) The only thing I would change if I had to do it over again is I would have installed a 4 ton unit. The hot water hook up does take btu's from the air temp. If the system doesn't run often enough, the exiting air temp is noticeably cooler until the aux hot water tank comes up to temp.( It was with my insistance the installer used a 5 ton, he recommended a 4. I guess I should have listened.) The system works the best during Jan, Feb and March, when it has to operate more often, but rarely runs steady as I think it probably should. All in all I'm very happy with the operation, I think it would have saved money on the installation and operation of the unit had I done what the installer recommended.
    Canuk
     
  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Thanks

    I needed to hear about working pond loop systems.

    Mark
     
  3. ChrisJ

    ChrisJ Active Member Forum Leader

    Canuk,
    When I first looked into geo for our new house I thought it was better to oversize or at least meet 100% of the load. I didn't understand (at the time) that there could be a savings in the long run to meet less then 100%. Small amounts of aux use would have saved possibly thousands in install costs.

    I really wish I had spent the time to read here on the forum back then!! My thanks to everyone here.

    ChrisJ
     
  4. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Why didn't they put the entire loopfield into the pond? Why a hybrid?
     
  5. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    A good point. You are not alone, I have customers who have done the same thing.
    Ultimately I will give a customer what they want as long as I know it will work but If someone hires an expert, it would seem like a good idea to leave the expert in charge of the design.
    j
     
  6. canuk

    canuk New Member

    Since the pond is only 7 1/2 feet deep at the deepest point, I didn't think it had the depth to support the entire load. We ran the trenches close to the pond , down close to 6 feet. I
    thought there might be some benefit having the trenches as close as possible to the pond, but who knows. It does work well.
     
  7. canuk

    canuk New Member

    I know, your absolutely correct Joe. I just couldn't resist getting dirty, and I warned the installer I was the type to stick my nose into things. We worked together, the install went smoothly, and the system works great. I'm a happy (warm) camper.
     
  8. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Keep in mind that the volume and mass you have for heat exchange is far greater in bodies of water than in horizontal trenches (in your case far less than 1/2 acre), with far superior heat transfer capabilities.
    A pond will also stratify, feeding the tubes on the bottom with the warmest water.
     
  9. canuk

    canuk New Member

    Another year gone by, system still working perfectly.
     
  10. canuk

    canuk New Member

    Thought I'd pop in and give another update. This is the coldest, snowiest winter I can remember since I was a kid. The furnace is a two stage unit, and it has been kicking up on high quite regularly for the last 6 weeks. I have no electric back up built into the system, but the system has been able to easily keep up so far without it. My loop temperatures now, are the coldest I've seen. Approx 35degrees coming in, and 29 going out. (probably not completely accurate, as I took the temperature with an infared thermometer, but you get the idea) I'm very happy with the system performance, and the even temperatures throughout the house.
     
    johnny1720 likes this.
  11. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Thanks for the update. This winter has been separating the men from the boys in design planning. Sorry girls, separating the girls from the women.

    Mark
     
  12. canuk

    canuk New Member

    Another year gone by, and, yet again, everything is working perfectly. All I've done so far is furnace filter cleaning. Any other routine maintenance that should be done? My only complaint is with the hydro rates which seem to be really cranking up. I'm thinking about adding a 5kw solar system on a net-metered basis to help offset some hydro costs.
     

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