Standing Column vs. Closed Loop System

Discussion in 'Geothermal Loops' started by CT Geo, Apr 6, 2009.

  1. CT Geo

    CT Geo New Member

    I am progressing along in my search for a GSHP system/installer. I have asked four installers for quotes for my job. One of them is recommending a standing column well, the three others are advocating for a closed loop. The installers that are advocating for the closed loops are saying that maintenance (pump, etc.) is an issue with the standing column, and that they would recommend strongly against a standing column. I have also spoken with two well drillers that cautioned against the standing column.

    The one installer that is a proponent of the standing column has admitted that there could be increased maintenance, but that is more than made up by the lower installation and operating costs (higher efficiency). This installer uses Climatemaster equipment (as does one of the closed loop installers). I have called the local distributer for Climatemaster, and they say that both installers are reputable and both well options are viable.

    Any thoughts on this issue would be appreciated.
     
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Decision

    CT,

    Sounds like you've got most of the info. in front of you and you'll need to make a decision. Closed loop is obviously less maintenance and can have lower operating costs due to pumping power requirements (closed vs. open). If it was purely an economic decision, then you look at the additional operating costs vs. additional capital costs. If it is +$4000 (or whatever) to install closed loop and save ($200) year, then, on a number's game, it doesn't look like it makes sense. But, sometimes client's just want the piece of mind with closed loop - you need to figure out what that is worth to you.

    You'll always get proponents/opponents for all sides. But, done right, they all work, and work well. Time for you to decide.

    You can always ask the installers if they have experience in the other installation methods.
     
  3. CT Geo

    CT Geo New Member

    I had thought about that, but decided against it. My rationale was that I wanted each installer to offer their "best" solution for my situation.

    I am leaning toward the SCW. My biggest concern is that those that are advocating against it are very adamant that this is not the way to go, and they are in the majority.
     
  4. jongig

    jongig Member

    First let me say up front that I don't think SC-GT should be used ever and my opinion has a bit to do with the fact that I'm a licensed water operator. Having said that, both work very well in the beginning but you'll always worry about what the water is doing to the exchanger over the years with SC. The complaint I have is with the water and that even if you test the water today the water will change over the next 20 years. Also in my well experience I see fluctuations in water levels in wells by 50-100 feet over just a few years and I see this rarely considered. I’m sure the CL-GT costs more but it just makes so much more sense. I might consider talking to someone that is in the water business in your area and see what they say about running the water through an exchanger.

    john
     
  5. CT Geo

    CT Geo New Member

    I did voice this concern to the installer that is recommending the SCW. They indicated that the Climatemaster has an option for a Cupro-Nickel heat exchanger that will resist corrosion from water conditions. I also agree about the water level concern. I will ask this of them and see what they say.

    When you say that you would consider talking to someone in the "water business" in my area, what exactly do you mean? Where/how would I find such a person?
     
  6. Looby

    Looby Member Forum Leader

    The promise of "higher efficiency" is questionable -- and even if true, the
    difference in operating costs will be very small compared to a competent
    closed-loop installation.

    I was originally leaning toward a pump-and-dump system because of its
    "higher efficiency," until I did the calculations. A few tenths improvement
    in COP for 50F versus 35-40F EWT would save me less than $100 per year
    (for a 3-ton heating-dominated installation). Standing column would save
    even less (if anything).

    The trade-off between initial installation cost and maintenance is real, but
    the promise of higher efficiency/lower operating cost is largely imaginary.

    Looby
     
  7. jrh

    jrh Member

  8. jongig

    jongig Member

    I'm not going to spend too much time on the water part but you've got an exchanger in the house and underground. Besides the increase in cost for pumping instead of circulating you'll have higher costs for replacement in the future. You will have to call a well driller to replace the pump and it's expensive. My wells are in my back yard underground never to be seen again and your's will be visited by big trucks in the future. They make smaller pump pulls but here in PA most use big trucks. So you fix up the yard and next year you get hit by lightening and loose a pump and they rip up the back yard. When my pump goes in January it's just a visit from the installer and an hour later I'm up and running.

    I was just suggesting you have some contact with someone that works with well water in your area. You can look in the yellow pages under water and try to make contact with a licensed operator.
     
  9. CT Geo

    CT Geo New Member

    Thanks for the image, Jon. I do like the "drill and forget it" nature of a closed loop system. I do not like the idea of a well driller driving through my back yard to replace the well pump after an electrical storm. I'll add this to the list of questions for the SCW installer...

    Looby, I myself was skeptical of the lower operating cost/higher efficiency promised by the SCW installer - I was only pointing out his rationale. My understanding (albeit limited, as this is not my area of expertise), is that the increased efficiency is demonstrated by the shallower well necessary to service the same space when compared to a closed loop. This translates to a lower install cost, but I will need to wait for their quote to see exactly how much this really equates to.
     
  10. Geo1Me

    Geo1Me New Member

    CT,
    I just installed a 4 Ton Waterfurnace Combination unit in my own home in Maine. I did all the research on the various units and on the different options over a two year period. the quest for information was a blast. I went to all the "pros" in my area and found the case for or against open loops well defined and very opinionated. We run a well services company, Drilling, pump service and water filtering is how we make a living. When I heard the proponents of running raw water through these wonderfully efficient GSHP units I had to question," what happens the day your well water has Iron Or Manganese or silt or a few other problems like bacteria in it?" and one of the proponents actually had the audacity to look me straight in the face and say,"well, when the system plugs up, they'll just have to call me for a service call to acid wash the heat exchangers, and that makes me more money."
    Let me give you a helpful piece of advice. I help folks solve water quality issues for a living and the last thing you want is to have a water quality problem in one of these awsome pieces of equipment. Your expensive system will never be right again and the new clean surfaces of you heat exchangers on the water side will never be as efficient after you have had a problem. You could be the lucky one that doesn't ever have a problem, but it's not worth the gamble. Closed loop is more expensive, but worth the comfort. Be careful, around here, most system failures come from poor water quality. Be smart, Be happy.
    There are some other major factors in the decision, cost of operation.
    When you have to move the vast amounts of water that one of these systems need to be most efficient. For my closed loop system, I must move 12 gpm, it runs about half of the time in the Winter, so that means I have to move around 260,000 gallons of water per month. For a S C well you have to do that with a well pump, it could cost you $60 to $100 per month. I move that volume of water with a Wilo wet rotor, Variable speed, ECM motor, type pump for an amasing $7 dollars a month.
    That alone will cover the extra costs of closed loops, even in Maine where that means drilling multiple wells in most systems. Again, good luck.
    Geo1Me
     
  11. Northern Apex

    Northern Apex New Member

    I would second what Geo said and add that depending on your location the quality of your aquifer can have some major dynamics. One well I own in a two year period has gone from 24ppm Iron, 2.4ppb Tannin and a modest Ph to 14ppm Iron, 4.3ppb Tannin and a very high Ph with the addition of Iron Bacteria.
    There are seasonal changes too. We have a season called "Breakup":D when all the ice goes out. Typically, the water levels can change as much as 30-40' and even with a 5 micron filtration system, we still get a lovelly hugh to the water for a couple weeks/month.
    More intitial expense and the elimination of so many variables. Smaller operating costs and a constant operating environment for your equipment.
     
  12. Guest

    Guest Guest

    Pumping costs for SC wells are the same as closed loop systems. The work in pumping upward is canceled out by the water flowing downward.

    If you pump water from a well and dump it on the surface, you will have higher pumping costs than a closed loop system.
     
  13. CT Geo

    CT Geo New Member

    Thanks for all of the insight. I've narrowed my decision to going with a Climatemaster installer. Their recommendation is to do a SC well, with Tranquility 27 equipment with the Cupro Nickel Heat Exchanger option. My understanding is that this heat exchanger is more resistant to the corrosive effects of various groundwater conditions. They are also providing a ten year warranty - I have asked to see the language on this to see if it covers issues caused by groundwater conditions. The well driller is also giving me a warranty on the pump and his well.

    I am still scratching my head here. Part of me is saying that I should eliminate as many variables as possible and go with the closed loop, the other part is saying that I should go with the SC.
     
  14. jrh

    jrh Member

    what is your heat load? how deep do they want to go with the scw? good luck
     
  15. Guest

    Guest Guest

    I think you will be fine with that choice.

    I believe that deposits, not corrosion, is the thing to watch out for. So you may have to clean the heat exchanger now and then.
     
  16. CT Geo

    CT Geo New Member

    Fast forward a few months. The well drillers were out at my house with their rigs to dig for the standing column well. They started digging on Tuesday (9/22). By Wednesday (9/23), they had determined that there was an issue with hitting solid bedrock - there was plenty of water but all of the rock that they did hit was fractured, which is problematic for a SCW (or so I am told). They are now working up a price for switching to a closed loop system.

    I hope to hear from the well driller later to day regarding the additional cost for this work. Since the well driller and GSHP installer both advocated for going with the SCW over a closed loop, does anyone have any advise on how I should handle the negotiations on this issue?
     
  17. gabby

    gabby Member Industry Professional Forum Leader

    I think you have all the information you need to make a decision. You have already stated you don't want a 50,000 pound truck in your backyard in 2,4, or 6 years from now. The question is when, not if.
    What are you going to do with 1 million gallons (more) of water that you will pump through your system annually?

    No matter the system design, or the manufacturer, maintenance will be part of the future....plan accordingly keeping your comfort zone in mind.
     
  18. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    I think negotiations start at the beginning. Depending on how far into the job they are, there's nothing to keep you from reopening the bidding process. I don't recall if horizontal was on the table for you but that is less expensive than vertical closed.
    Odds are SCW was going to be less expensive than your other choices and while there is no harm in asking for consideration you obviously don't expect them to eat the whole thing.
    It is an opportunity for you the contractor and the well driller all to share in the price difference vs you bearing all of it. It is an opp for them to get they're butts out of a sling by working for a little less, while you recieve the benefits of closed loop at a cut rate.
    It's a lesson for all shoppers to ask "what happens if you can't dig an SCW?"
    Good Luck,
    Joe
     
  19. CT Geo

    CT Geo New Member

    I had a meeting with the well driller at the property prior to executing the contract, and he indicated that there should be "no reason" that they would not be able to do a SCW. Pretty funny, looking back at that now...

    I had not considered a horizontal loop because my preliminary research was that that was an inferior option (when compared to SCW or vertical closed loops). Is that not the case? Should I now be looking at doing a horizontal loop? My lot is about 1/2 an acre, so this may be a limiting factor here (slinky loops may make this a more viable option). There are slight grading issues in my backyard that this would allow me to correct at the same time.

    In telephone conversations with the well driller and the Geo Installer, I have gathered that there is an increase of almost 65% to switch from the SCW to closed loop. The driller told me that he is "eating" the $7,000 that he "wasted" by having his rigs and staff at my property for two days. I have a face to face meeting scheduled for next Tuesday - we'll see where that goes...
     
  20. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    sorry can they dig scw or not? if it is an option and they gave you a flat fee for digging it then driller might have bad luck, but the "wasted 7k" not your problem.
    Horizontal on a half acre tricky depending on demand. I believe my confusion is shared ......can they or can't they dig an scw?
    if not, and there are circumstances impossible to forsee it would be rightgeous to share added cost. If 2+ other bidders predicted this while current contractor said it could be done then......(not your problem).
    j
     

Share This Page