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  1. #1
    Join Date
    Mar 2009
    Location
    Northeast WI
    Posts
    25

    Pulled the trigger! Wall of fame or wall of shame?

    Howdy!

    I just gave the official "yes" to a geothermal proposal I've been mulling over for about 30 days now.

    I just thought I would share the details of the proposal (minus price of course) with everyone to make sure I can post the results of the install on the wall of fame and NOT on the wall of shame.

    Location: Outside Green Bay, WI
    Home size: 4913sq ft TOTAL - 1st - 2028sqft 2nd - 857sqft Basement - Unfinished, will finish later!
    Orientation: Facing North, most windows on South side
    Insulation: 2x6 with R-23 BIBS, R-50 attic, foam attic seals, foam box sills
    Heat Load: 60,189Btuh
    Cooling Load: 25,077Btuh
    Electric Cost: $.12
    Gas Cost: $1.25

    Proposed System:
    WaterFurnace Envision ND049 ECM
    12 60' trenches @ 8ft depth w/ 500ft of slinky in each (6000 total feet)
    Electric auxiliary internal duct heat 8kW
    Envision ND dual capacity Series Water Unit
    Electric with GeoAsist Water Heater
    3 Zones
    RenewAire ERV

    Heat calc and job info attached for your destruction.
    - Loop seems kind of fat, and WF unit seems kind of small, but I don't know jack, and all the math seems to work, let me know if I'm nuts.
    Attached Images Attached Images      

  2. #2
    Join Date
    Feb 2004
    Location
    Pacific NW
    Posts
    566
    ... a query to the moderators.. before violating any rules...

    Permissible to copy and paste a pro forum description of shop built evaporators for GSHP (system COP=5.6) better than anything commercially available? .. here?

    Posted it in the pro geo section as a manufacturing possibility for energetic and aggressive young guy going into the business, but 'so simple', that in open area probably would be considered DIY??

  3. #3
    Join Date
    Mar 2009
    Location
    Northeast WI
    Posts
    25
    I'm not sure I follow, but I'd love to see it. Otherwise if it can't go here, you can e-mail it to me. thenuke -at- gmail dot com

  4. #4
    Join Date
    May 2005
    Posts
    160
    Well given the drastic difference between your heat gain and heat loss I guess they chose a good size unit. You should be pretty happy with that setup. My only concern is the loop design. I hope they don't plan to do 6 parallel loops. They are probably going overkill on how much pipe they are burying as well. All-in-all it looks good. My choice for your heat gain and heat loss would be a dual fuel setup with a little 2 ton geo unit and a gas furnace.

  5. #5
    Join Date
    Mar 2009
    Location
    Northeast WI
    Posts
    25
    Quote Originally Posted by crash11 View Post
    Well given the drastic difference between your heat gain and heat loss I guess they chose a good size unit. You should be pretty happy with that setup. My only concern is the loop design. I hope they don't plan to do 6 parallel loops. They are probably going overkill on how much pipe they are burying as well. All-in-all it looks good. My choice for your heat gain and heat loss would be a dual fuel setup with a little 2 ton geo unit and a gas furnace.
    Thanks. Not being an expert, what kind of loop design should I be looking for? And better too fat than too skinny, right?

  6. #6
    Join Date
    May 2005
    Posts
    160
    Well, if they are burying that much pipe I'm sure they'll be using 3/4". Also, in a 4 ton system you want 12 gpm total flow (the industry likes to use a 3 gpm per ton guideline). According to my tables the best flowrate using 3/4" pipe is around 4 gpm. Too little and you are in the laminar flow region, and too much is just wasteful turbulence. So if you want a TOTAL flowrate of 12 gpm then that means you want 3 parallel loops (4 gpm for each loop = 12 total). That's what you want to look for is how many parallel loops they are running. Additionally, if they are professionals they will arrange their header in a reverse/return fashion. Lastly, I've been told by my unit's manufacturer (fhp) that you don't want too much total flow or too little. So make sure they verify you're getting 12 gpm exactly (+/- 0.5 gpm). I was told too much flow causes the unit to not work properly in heating season.

    Edit: I did a little digging and found the pressure drop you should be looking for on your unit. The way they figure out system flowrate is by measuring the pressure difference between the two diagnostic ports on your pumping station. Anyway the pressure drop should be around 3.8-3.9 psi depending on the temperature of the water.

  7. #7
    Join Date
    Jul 2006
    Location
    Southern Ca, Elkton Md
    Posts
    7,570
    Hmmmnnnn.....

    Something souds a little off to me.

    Your last page indicates the min and max loop temps.

    Min looks good, max looks to low.

    But it is a little hard to read.
    "Correct Installation is the Key"

    .1 has killed more HX then Rush Limbaugh

    What is your TESP?

  8. #8
    Join Date
    Jul 2006
    Location
    Southern Ca, Elkton Md
    Posts
    7,570
    That is a good piece of equipment, dual capacity, variable speed.

    What will they be using in the loop?
    "Correct Installation is the Key"

    .1 has killed more HX then Rush Limbaugh

    What is your TESP?

  9. #9
    Join Date
    Jul 2006
    Location
    Southern Ca, Elkton Md
    Posts
    7,570
    And did you get the 55 year warranty on the loop?
    "Correct Installation is the Key"

    .1 has killed more HX then Rush Limbaugh

    What is your TESP?

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,874
    [QUOTE=junkhound;3061712
    Posted it in the pro geo section as a manufacturing possibility for energetic and aggressive young guy going into the business, but 'so simple', that in open area probably would be considered DIY??[/QUOTE]

    No.

    That would be DIY instructions.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  11. #11
    Join Date
    Mar 2009
    Location
    Northeast WI
    Posts
    25
    Quote Originally Posted by weber View Post
    Hmmmnnnn.....

    Something souds a little off to me.

    Your last page indicates the min and max loop temps.

    Min looks good, max looks to low.

    But it is a little hard to read.
    Thanks. Min is 30 and max is 64.5. That's too low? Really?

  12. #12
    Join Date
    Mar 2009
    Location
    Northeast WI
    Posts
    25
    Quote Originally Posted by weber View Post
    That is a good piece of equipment, dual capacity, variable speed.

    What will they be using in the loop?
    When you're asking what they'll be using in the loop, what do you mean exactly? What's actually running through the loop?

  13. #13
    Join Date
    Mar 2009
    Location
    Northeast WI
    Posts
    25
    Quote Originally Posted by weber View Post
    And did you get the 55 year warranty on the loop?
    I did not, I'm assuming by your phrasing that I should...

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