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  1. #14
    Join Date
    Aug 2009
    Location
    Lititz, PA
    Posts
    4
    Here in Central PA, the average well is 150-165' per ton. Carrier and Climatemaster are the same. We always use 2 speed units with ECM motors, and desuperheaters. This generally equates to the purchase of high end air-to-air equipment, but with 2 or more times the eff. The homeowner gets his 30% which just about covers drilling. We're now doing more direct refrigerant systems than propylene, using a new approach that addresses oil return issues.. and the wells aren't as deep.
    PA school systems have been doing more and more geo over the last 15 yrs. They started out using boiler-tower setups, but now design puts wells under football fields. There are individual h/p(s) installed with 2-way valves in each room with VFDs in the mechanical rooms.
    Geo doesn't get you off the grid..but with deregulation coming in PA, facilities and homeowners are looking at rates to rise 35% +. This is being done here without any support from state government.
    Look to your distributor for educational opportunities.

  2. #15
    Join Date
    Apr 2008
    Location
    Northwest Arkansas via Chicago Area via Straight Up from There on Lake Superior
    Posts
    1,411
    Quote Originally Posted by aluckyskunk View Post
    Here in Central PA, the average well is 150-165' per ton. Carrier and Climatemaster are the same. We always use 2 speed units with ECM motors, and desuperheaters. This generally equates to the purchase of high end air-to-air equipment, but with 2 or more times the eff. The homeowner gets his 30% which just about covers drilling. We're now doing more direct refrigerant systems than propylene, using a new approach that addresses oil return issues.. and the wells aren't as deep.
    Maybe not. I got actual proposals and after rebates and tax credits, geo was closer to 2 times a high end DFHP. I wanted to go geo but in my case I would never recover the cost. Run the numbers and compare!

    Quote Originally Posted by aluckyskunk View Post
    PA school systems have been doing more and more geo over the last 15 yrs. ...
    Just read where smaller school districts here in Arkansas are applying for Fed stimulus grants to go geo. Some of the larger ones are already doing it. Of course AR is the home of a huge geo advocate for many years, Doug Rye, architect and energy efficiency expert.

  3. #16
    Quote Originally Posted by aluckyskunk View Post
    Here in Central PA, the average well is 150-165' per ton.
    Lucky - I have been looking into a geo for my house in SE PA. Well depth is something that is causing me some concerns. Are you doing four wells at 150-160' for a four ton? Do you know what the average well depth is in SE PA? I have received three quotes and they are all suggesting two wells at 150' for four tons, or, 600 feet of tubing. Down in Southern Delaware, I understand they do 1 well per ton at 100 to 150 feet.

    I have some comfort with the fact that all three recommended two wells at 150 for a four ton, but these recommendations seem to be less depth/wells per ton than I am reading people suggest/use in other locations.

    Also, I don't understand your point re deregulation in PA. That's just for the electricity, correct? If so, why would that be a good thing for a geo? I'll admit, I'm confused on this one, but my understanding is that my electricity usage will likely go up with a geo (my natural gas usage will go down). If the price of electricity goes up 30% to 35%, but natural gas doesn't, don't I want to stay with heating via natural gas? From the analysis that I have seen re my house, the lion's share of the savings is when the system is providing heat. Is the answer that it's more efficient (than natural gas) even with the 30% to 35% increase?

    Anyone else have some thoughts for me on these questions?

  4. #17

    GeoConsumer

    [QUOTE=GeoConsumer;4821082]- I have been looking into a geo for my house in SE PA. Well depth is something that is causing me some concerns. Are you doing four wells at 150-160' for a four ton? Do you know what the average well depth is in SE PA? I have received three quotes and they are all suggesting two wells at 150' for four tons, or, 600 feet of tubing. Down in Southern Delaware, I understand they do 1 well per ton at 100 to 150 feet.

    You should be looking at somewhere between 150-200' of well boring per ton in SW PA. This is dependent upon the local ground conditions with higher thermal properties directly related to rock density and silica content. The more loop that can be installed under the groundwater table the better as well. Unsaturated sand overburden would require the generally require the most loop per ton. Some of our recent thermal conductivity tests in Lancaster in dense metamorphic rock showed about 150' of boring per/ton.
    In summary, you really need to look at the subsurface geology but the 75' of boring per ton isn't likely with water source.

    -Adam
    Hydrogeologist

  5. #18
    [QUOTE=GeoConsumer;4821082]- I have been looking into a geo for my house in SE PA. Well depth is something that is causing me some concerns. Are you doing four wells at 150-160' for a four ton? Do you know what the average well depth is in SE PA? I have received three quotes and they are all suggesting two wells at 150' for four tons, or, 600 feet of tubing. Down in Southern Delaware, I understand they do 1 well per ton at 100 to 150 feet.

    You should be looking at somewhere between 150-200' of well boring per ton in SW PA. This is dependent upon the local ground conditions with higher thermal properties directly related to rock density and silica content. The more loop that can be installed under the groundwater table the better as well. Unsaturated sand overburden would require the generally require the most loop per ton. Some of our recent thermal conductivity tests in Lancaster in dense metamorphic rock showed about 150' of boring per/ton.
    In summary, you really need to look at the subsurface geology but the 75' of boring per ton isn't likely with water source.

    -Adam
    Hydrogeologist

  6. #19
    Join Date
    Sep 2008
    Location
    Central Florida
    Posts
    40
    Hey down2earthgeo, how about florida? zip code 33881? What say you?

  7. #20
    Quote Originally Posted by protechplumbing View Post
    Hey down2earthgeo, how about florida? zip code 33881? What say you?
    Regarding vertical loops, Central Florida's subsurface geology is highly variable with surficial sands, silts, clays underlain by limestone. The main variable for loop design is how much overburden you have before hitting rock. With the variability you have, you really need to put a hole in the ground onsite or find a nearby well to examine the drilling log. With that said, the one thing you have going for you is a very shallow water table expressed with numerous lakes/ponds. These means almost all of any loop will be saturated. So you are in good shape regardless of whether the loop is in rock or sand--although the more groundwater flow the better so the more fractured/dissolutioned the rock the better.

    However, one more variable comes into play in deciding the length of ground loop which is the subsurface temperature. Here in PA, our mean earth temp is about 51 degrees while in central Florida it's about 74 degrees.

    74 degrees is great for heating but not as good for cooling. Since you have to design for the cooling load in FL, you are generally looking at the upper range of around 300' of boring per ton but you really need to put in your site-specific criteria into loop design software to see exactly what you need.

  8. #21
    Join Date
    Sep 2008
    Location
    Central Florida
    Posts
    40
    At 300' bore per ton, I would be looking at 1200' feet total for a new 4 ton geo system. I'm not sure going geo would be an economically sound decision in my situation. I would estimate that the ground loop alone would cost $K plus the added cost of the equipment. I can get an 18 seer goodman system complete (with me doing the install myself) for $. It looks like the geo system would cost about $k. I don't know how to convert EER to SEER to compare the operating costs of the 2 systems but it would seem that the geo system wouldn't pay for itself in a reasonable amount of time. Even with a projected annual energy inflation of 5%.
    Last edited by beenthere; 10-27-2009 at 01:40 PM. Reason: Removed prices

  9. #22
    Quote Originally Posted by protechplumbing View Post
    At 300' bore per ton, I would be looking at 1200' feet total for a new 4 ton geo system. I'm not sure going geo would be an economically sound decision in my situation. I would estimate that the ground loop alone would cost $K plus the added cost of the equipment. I can get an 18 seer goodman system complete (with me doing the install myself) for $. It looks like the geo system would cost about $k. I don't know how to convert EER to SEER to compare the operating costs of the 2 systems but it would seem that the geo system wouldn't pay for itself in a reasonable amount of time. Even with a projected annual energy inflation of 5%.
    In Florida (and other areas with high ground temperatures) geothermal can be a tough sell in competition with air source. However, the 30% federal rebate certainly help level the playing field.

    Open Loop geothermal (i.e. pump and dump) is a good option in Florida since water quantity/quality tends to be high and a single well with a nearby pond/ditch to discharge into is cheap. Florida Heat Pump is big on these. Lastly, an option that often only requires half of the drilling is DX geothermal with local manufacturer www.earthlinked.com being the leader.
    Last edited by beenthere; 10-27-2009 at 01:44 PM. Reason: Removed prices from quote

  10. #23
    Join Date
    Apr 2008
    Location
    Northwest Arkansas via Chicago Area via Straight Up from There on Lake Superior
    Posts
    1,411
    protechplumbing, not sure that the moderator will like your price details. But I recently did a high end upgrade and I asked for proposals on DFHP and geo. After all rebates and Federal tax credits on both (I don't have the great local, state and utility credits in other states), the geo came in at almost double the high end DFHP in our area. You have to run the numbers but for our modest total electric/NG yearly costs. I would never recover that premium in my situation.

    Just curious if you have compared DIY with a contractor install with name brand manufacturer. I imagine that you get no rebates if you DIY and sounds like the warranty is iffy. After all rebates/credits, I got a certified manufacturer installation with 2 added IAQ units (media filter and UV lights) along with a 10 years parts and lifetime coil plus 1 year labor for about 50% more than you claim your cost is. Is it worth the risk?

  11. #24
    Join Date
    Apr 2008
    Location
    Northwest Arkansas via Chicago Area via Straight Up from There on Lake Superior
    Posts
    1,411
    Quote Originally Posted by down2earthgeo View Post
    ...

    However, one more variable comes into play in deciding the length of ground loop which is the subsurface temperature. Here in PA, our mean earth temp is about 51 degrees while in central Florida it's about 74 degrees.

    ...
    D2EG, I'm a bit confused by your ground temps. How deep does the 74 F go? I thought that down 3-4' the temp would be much lower.

    However, I got a bit turned off when a geo contractor told me the loop high temp resulting from a hot summer of AC. I think it was even higher than you mention. Is that what you refer to?

  12. #25
    Join Date
    Sep 2008
    Location
    Central Florida
    Posts
    40
    sorry, i forgot about the price thing.

  13. #26
    Quote Originally Posted by jerryd_2008 View Post
    D2EG, I'm a bit confused by your ground temps. How deep does the 74 F go? I thought that down 3-4' the temp would be much lower.

    However, I got a bit turned off when a geo contractor told me the loop high temp resulting from a hot summer of AC. I think it was even higher than you mention. Is that what you refer to?
    I'm talking about the mean earth temperature which is the temp at about 30' down which is generally consistent with groundwater temps. The temperature fluctuates above 30' by up to 40 degrees throughout the year. A good explanation including a map can be seen at http://www.geochoices.com/soil_and_g...onditions.html

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