Municipal geothermal loops

Discussion in 'Quotes and Proposals' started by Matt Chambers, Jul 9, 2011.

  1. Matt Chambers

    Matt Chambers New Member

    I don't have a geothermal heat pump, but I think it's a tremendous idea to reduce energy usage without sacrificing comfort. Why don't (more?) municipalities provide geothermal ground loops like they do sewage and water pipes? It seems to me they could and should be laid together. Tapping into the loop would have some monthly service fee but only for maintenance, not for consumption (unlike water usage). In other words, cheap cheap cheap.
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Think sewage

    Sewage makes more sense than the water.
  3. GCI

    GCI Member

    Loop Tariff

    There are a few utility companies out there that are installing loopfields.

    Once example:

    Earthwise Geothermal Program EarthWISE res.pdf

    With programs like this, there are no up front costs (that I know of) to the homeowner to install the field. The utility company covers the installation cost for the loops and then charges a tariff on the utility bill to recoup their investment.

    The utility looks at the loopfield as infrastructure, using a concept similar to how they've historically paid for power line installation.
  4. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader


    I should add that it is common to have a utility/subdivision setup around here.

    The plus
    - you don't pay for the ground loop

    The minus
    - you likely don't get an optimized design (ie- buy whatever heat pump you want)
    - you pay utility + operating costs
    - more focus on capacity than savings (ie-they will oversize as a general rule of thumb)
  5. BobD

    BobD New Member

    So in my town there are no such loops. Is there a way to use the residential water coming into my home as the water source?
  6. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Yes. But NO. Which means - mechanically for sure, but 1,000,000 gallons of water wasted per year per house would put an end to that.
  7. Matt Chambers

    Matt Chambers New Member

    Interesting! What is a typical flow rate of geothermal pump system? How much water would cooling your house in the summer use compared to watering your lawn, for example? Would the level of "waste" even be comparable or is one vastly more efficient than the other?
  8. BobD

    BobD New Member

    Wow! Didn't think the volume would be that high. Just to clarify that the residential water is my well, the intent was to use as heat only, in our climate cooling is not necessarily needed. I would estimate approx. November through to March would be the extent of the use. Not sure if that changes anything but would appreciate opinions.
  9. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I am sure Chris is talking Canadian for waste water treatment. Here in my little corner of Ohio they base our pay to play rate on water coming into a house. Some towns give you a reduction water meter for lawns. Making the grass grow does not contribute to the sewer thing.

    I fell your pain, but why send cleaned city water through a heat pump?
  10. BobD

    BobD New Member

    I have two options, I have my own well and I also have a residential feed. In our neck of the woods water is abundant and there is no fee or metering, so its free. Well I still pay taxes which cover the water and other services. A coworker began to tell me about these heat pumps and how they can transfer the heat from the water to my hydronic heat system. And here I am trying to learn more. I have a new house built todays standards /codes, 3000ft. Sounds like either supply has the potential just trying to better understand before I jump in. My well water is better quality than the towns so I would be leaning in that direction. Sounds like it is possible?
  11. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    I know of it being done (as in a local arena around here). That is, a heat pump being connected to a domestic water system. But, as a professional, I would never do it. Huge waste of water.

    A well system, sure. Depending on the region, a very common practice. ideally, the water is returned to the aquifer it comes from.
  12. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    I know of several municipalities that allow municipal domestic water to be used for GSHP and the water is returned at a higer pressure to the main. I am not a big fan of that concept..... but if the choice is geo or no geo, I would prollly do it.
  13. Matt Chambers

    Matt Chambers New Member

    Are you "not a big fan" in the same way that 3rd party mechanics are not fans of electric and hybrid cars (i.e. they're bad for business), or is there more to it? :) It seems to me that if the main-to-house-to-main system was upheld to a sufficiently high standard of reliability and cleanness and only installed by licensed professionals (like natural gas connections), it would be a safe system to use and waste essentially no water. I didn't realize that returning water to the main was even an option until you mentioned it so I'd like to hear the cons. I can imagine the water not being as reliable in temperature as a true ground loop.
  14. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    There's a fair amount to it. Domestic water and refrigerants for example. What do you when you down a water main and everybody's heat goes out? Public/private rights. etc.

    As an engineer, it certainly can be done.

    I'd be far more interested in sewer waste heat recapturing.
  15. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Was there not a thread a while back about putting the loop field under the septic system leach bed?

  16. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader


    Yeh, but the septic guys want engineered backfill if native soils are disturbed, so the costs can take away any incentive.
  17. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    The cons are what Chris expressed. The potential risks to the general public, outway the benefit. The number of HX coil failures are common enough that to me it is a non starter that I am responsible for someones kids drinking a contaminant I created.

    I love the concept of the " poop loop ". I have also thought about putting loops below a under parking lot stormwater field where there is a fair amount of stormwater during the hot months to help cool the loops.
  18. Matt Chambers

    Matt Chambers New Member

    It seems climate and the level of urbanization make this a rather subjective issue. I've always had access to municipal sewage (unless you're talking about loop fields that go all the way back to the waste treatment facility?). Anyway, I don't know the significance of sewage waste heat to me, but I know that cooling is as important an area to optimize for energy savings in Tennessee (where I live) as heating. :)

    I am pretty skeptical about the risks to the general public necessarily outweighing the potential benefits. You could say the same about natural gas connections to homes. Those occasionally explode too. :eek:
  19. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Localised weapons of gas destruction are one thing. You start talking about the potential for contaminateing a water service that serves many homes and families and yoU will find yourself on a watch list. The gas distribution analogy does not hold up unless you are going to pipe some natural gas into your home, take some btu's out, and then replace the used btu's with enriched uranium to send back down the line to your fellow town folk.

    In te case of the poop loop we are talking about private onsite sewage disposal for the majority of single family homes in suburb/rural USA.
  20. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    We have burning ice in Japan and burning water in PA. I do not think an out and back muni water system is a good idea if it includes potable water.

    I do not know if a child fed R-410A in his drinking water, down hill of my leaking geo unit will die, but why take the chance.


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