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  1. #1
    Join Date
    May 2008
    Location
    Grand Haven, MI
    Posts
    14

    Geothermal Open Loop Water Quality

    I recently discovered this forum and am learning a lot. Thanks to all who contribute here!

    I have a 15 year old house in western Michigan that I would live to convert to geothermal. Propane prices are horrible and the deliveries are a nuisance due to a long, hilly drive and lake effect snow. I have lots of land for a closed loop, and tons of water for an open loop.

    I would like to try an open loop system to keep my initial costs down. I could potentially convert it to a closed loop in a year or two if it proved problematic. The biggest obstacle I have is water quality. We have tannins in the water and a modest amount of iron.

    My question is whether there is something that could be done to improve my water quality. I recently met someone that was running their geothermal unit through their water softener. This sounded nuts to me, but it did cause me to wonder whether there is a compromise here. Assuming I only want to improve the water enough to avoid scaling (not necessarily drinking quality), is there a cost-effective way to do so? Is there another out-of-the-box approach that I might be missing?

  2. #2
    Join Date
    Nov 2007
    Posts
    86
    I would suggest installing a closed loop system from the outset – particularly if your water quality is questionable. Look for a design that will likely be the most trouble free from the start. This is an expensive project to revisit – especially when you’re freezing!

    Calculated over a 20-year life cycle, closed loop usually works out to be the most economical, all things considered.

    IMO

    SR

  3. #3
    Join Date
    May 2008
    Location
    Grand Haven, MI
    Posts
    14
    Thanks for the reply. I am not opposed to a closed loop system, but it's really not in the budget right now (perhaps a year or two). However, due to a failure, we need to replace at least part of our current system now so I thought it might be a good time to take the plunge. Has anyone made an effort to try and improve water quality for an open loop?

  4. #4
    Join Date
    May 2004
    Location
    wiggins
    Posts
    77
    The open loop with improved water quality would be very expensive and the quality may change at a lter date. The open loop is the best and it can be cheaper only if you have a manner of disposal, such as a pond. A closed loop can be less painful down the road. I have researched this and asked a lot of questions to make a determination. I still do not have geo thermal.

  5. #5
    Join Date
    May 2008
    Location
    Grand Haven, MI
    Posts
    14
    I can dump water very conveniently. We have a high water table and soil is all sand. Even if I dumped it behind the house in the woods, it would disappear almost immediately and go right back to the same aquafier.

    I see systems such as http://www.easywater.com/ which claim to eliminate scaling without using salt. I am skeptical, but the parent company at http://www.freije.com/ claims to be doing this commercially as well. If something like this could cause the water to pass through without scaling, then maybe open loop could work for me.

  6. #6
    Join Date
    Mar 2003
    Location
    PA/DE area
    Posts
    1,535
    I had a PUMP and DUMP in my home in a GEO,and I did it due to LOOP costs.I spent more money in well pumps and valves and my wife nagging,I swore I would never do for another customer!! DO NOT MAKE the same mistake.
    It's NOT the BRAND,it's the company that installs it!!!!!

  7. #7
    Join Date
    May 2008
    Location
    Grand Haven, MI
    Posts
    14
    I appreciate the warnings about open loop and water quality. Let me ask a different question. Is it possible to add a plate and frame heat exchanger to the setup to isolate the well water from the system? I know this is done commercially. Are there residential versions of these that might be cost effective and would do the job?

  8. #8
    Join Date
    Apr 2005
    Location
    NE PA
    Posts
    698
    Quote Originally Posted by marcusj View Post
    I appreciate the warnings about open loop and water quality. Let me ask a different question. Is it possible to add a plate and frame heat exchanger to the setup to isolate the well water from the system? I know this is done commercially. Are there residential versions of these that might be cost effective and would do the job?
    This is one solution, but remember you will have an additional pump and the associated power, small loss in efficiency due to thermal loss in the exchanger and you will still need to be concerned over water quality since it is in the primary side of the heat exchanger. Sediment and corrosives can be as big a factor in the heat exchanger as with the heat pump. Only advantage is that your costly heat pump will be isolated from potential costly repairs due to the water quality.

    paul

  9. #9
    Join Date
    May 2008
    Location
    Grand Haven, MI
    Posts
    14
    Tecman: thanks for the feedback. My hope was that a plate and frame heat exchanger would not only isolate the geothermal system, but also be substantially easier to clean. I just don't know if they make one that is practical for a residential setting.

  10. #10

    Open loop works fine for me

    I live in Dorr Michigan and my water is also on the hard side. I used open loop for years without problem, you do want to be sure your well pump can handle cycling more, you should definitely have a large well tank or tanks and install a sediment filter on the inlet to the furnace. True, you may have to run a descaling solution every few years as maintenance and you need to get a unit with cupro nickel. My water table is 4 feet and sandy soil, if I ever go closed loop I will look into a pond with a loop at the bottom. I'm not here to argue with the pros that install this stuff for a living, but I know from my experience an open loop system with careful considerations can be rewarding. Jim

  11. #11
    Join Date
    May 2008
    Location
    Grand Haven, MI
    Posts
    14
    manx82: I am in Grand Haven - I think about an hour away. We may be dealing with the same contractors. I set my contact info to be visible. Please email me if you would like to compare notes.

  12. #12
    Join Date
    Jun 2008
    Location
    Marion, IN
    Posts
    81

    Open Loop Worked for Us...

    We have a open loop Water Furnace Geothermal unit that is almost 20 years old. We have used the same well pump with 2 pressure tanks and have never had a well problem. We have only had to replace 1 compressor and do the general yearly maintenance that is recommended. I would not hesitate to go with an open loop system again. Our water quality was not perfect either. I would advice you to talk to different professionals who are reputable and listen closely to what they suggest.

  13. #13
    Join Date
    May 2008
    Location
    Grand Haven, MI
    Posts
    14
    Rickochet: Thanks. I have received quotes from three professionals. They all seem knowledgeable, but their recommendations on open loop vary widely. Anyway, I'm taking the water to be tested and I'm gonna go from there. It's nice to seem some people with good experiences.

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