Coils vs. Racetrack

Discussion in 'Geothermal Loops' started by blimes, Mar 28, 2013.

  1. blimes

    blimes New Member

    Hi. Buidling a house this summer with a geothermal closed loop system with infloor heat throughout. Some of the geo guys go with a coil system with the pipe in the loop filed and some do a racetrack system where they just stretch the pipe out so the pipe isnt in contact with each other. What are some of the pros and cons to either system??

  2. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Doesn't matter. Find a good contractor and don't worry about loops.
  3. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    ditto to what Joe said
  4. ACES-Energy

    ACES-Energy Member Industry Professional Forum Leader

    We do it all, slinky, 2-pipe, 4-pipe, stacked, long as solid design and back up their loops with data or calculations, you should be good to go!
  5. Cain

    Cain Member

    Hello, I have had two contractors on site now. one specializes in loops and doesnt install furnaces. the other just Geo heat pumps subs the loops. the Furnace guy sized my home for 2.5 to 3 T. the loop guy designed loop that would handle a 5 ton system. 200 feet of 1.5 in to and from the header 400 total feet plus 3 600 foot slinkys out of .75 in. he said Reynolds will be 2552 with good EWT. I did question the furnace guy who use to do loops when him and his Dad use to work together. He, without software to help said they never used more than 400 ft / ton max. I suggested that I wanted to be sure I had enough loop and he said that will definitely be enough and running the circulation pumps is a minimal cost all things considered. Both of the guys are glad to let me do some of the work with the loop with them handling the fusing and flushing and connection to the QT flow center. All is good, my follow up to them was what if I still use 3 circuits manifold in the basement 600 ft ea. the key point being this. can I use two loop backhoe trenches 16" wide 5ft deep 3 600t circuits 1800 ft total? Both said that would be fine for my proposed WaterFurnace 3 ton model. FYI the furnace guy said he has only had to service two horizontal loops neither of which did he install with his Dad and one of them was older Polybutethsomething. So I have two expert opinions just looking for some re assurance about using my backhoe. obviously one pass with the bucket would be alot easier and straight forward. Thanks for any help / suggestions
  6. Cain

    Cain Member

    Geothermal 16 inch width two pipe trench Pros say ok

    Hello, I have had two contractors on site. One specializes in loop installations and the other is a HP installation guy that now subs his loops but use to work with his Dad and do the complete job. Details
    Sized for 2.5 to 3 T system - Furnace Guy has great rep with no loop problems from previous installs when he was doing them.
    Loop pro told me the field he designed would work for a 5T system. 200 ft 1.5" HDPE (400' total)to the header with 3 600' .75 slinky circuits all at 5' depth
    He quoted me fusing,flushing and QT flow center hookup with me doing the digging and with him doing entire project. Since the Furnace pro confirmed 3T system max, I have asked both pros this

    Can I use 16" wide (instead of the standard 24") two lines per trench side by side at 5' depth - 3 circuits 600' feet each manifold in the basement. My backhoe has a 16 in bucket and If I do trenches I can keep them closer to my entry point looping one circuit around my front yard and two trenches heading toward the back of my property.

    The furnace guy said he thought that would be more than enough when he was on site today (he said he use to install 400' per ton 6' depth with the loop over method top line 2' above bottom line dug with trencher) and those systems are still running well a decade later. The loop pro over the phone said he thought it would be fine as well. Again referring to his original 5T design and stating for 3T in my area of North Central Ohio would work just fine. I used the GeoComfort software just to see Reynolds and it is at 3371 with 9GPM calculated and actual and I only need 1200 feet total. PS the loop guy did numbers for 5T loop and it had 2552 R# with good EWT.

    any input / suggestions / confirmation would be appreciated. I really dont want to cut wood again this year...and Fuel is 3.50 / Gal.

  7. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    400ft/ton at 6ft and back at 4 ft sounds a bit short, but it depends on what the load on the loop is. Questionable that it will support a 5 ton load, but may be a 5 ton heatpump running only in 1st stage.

    But for your 3 ton heatpump, with a 2.5-3 Ton load, 3x 600' 5 ft deep in a 16" trench in north central ohio should should work fine.
  8. Cain

    Cain Member

    I was going to place 3 trenches in parallel 4 ft apart from ea. other. I ran into almost 100% sand. not saturated. so I am now going to run one trench to the front of my house and two wrapping around the back of the house. Question, do the circuits / trenches have to be the same shape. the front of the house will have 6 90 degree turns the two in back will have only 3 90 degree turns of course the turns will have sufficient arch to them as to not kink the tubing. (3/4 by 600')
  9. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    Shape does not matter, only length of pipe. Each 90° fitting counts a 10 feet of pipe. Pipe bent around a corner just counts as pipe.

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