1. Welcome Hearth.com Guests and Visitors - Please enjoy our forums!
    Hearth.com GOLD Sponsors who help bring the site content to you:
    Hearthstone Soapstone and Cast-Iron stoves( Wood, Gas or Pellet Stoves and Inserts)

New geothermal install

Post in 'The Green Room' started by sesmith, Nov 10, 2011.

  1. sesmith

    sesmith Member

    Joined:
    Dec 11, 2009
    Messages:
    223
    Loc:
    Central NY
    Just had a new geothermal (gshp) system installed recently and thought I'd put up some pictures for anyone looking into this. We've heated out house with wood and or forced air oil previously. Started out using mostly wood (wood stove in cellar), switched to oil for a few years back when it was cheaper (we installed a new furnace in 1987 and figured we needed to use it for a few years at least) and then switched back to wood full time a few years ago again, with the more recent addition of a solar air heater. Injured my back badly enough (while working on my firewood supply) this summer to take me out of the wood heating business, so it was either dump money into oil, or look at alternatives. We decided to bite the bullet on a geo system as our climate in central NY with it's cloudy cold winters and wet soil is ideal for geo. Payback over oil in our situation should be about 7 years with the 30% federal tax credit factored in.

    I started up by having an energy audit done on our place, resulting in me doing some rim joist air sealing, then found a geothermal installer who we totally trust knows his business. He did a great job on the installation. He's an engineer and is as meticulous with his installation as he is with his design calculations. He did recommend replacing and reconfiguring our ducting, something I'm really glad we decided to do. The system works great and keeps our place within a degree of the set point with absolutely no cold spots...a far cry from when we heated with wood or oil. We've only had the system in for a very short time, but have had temps down into the lower 20's, so far, before this recent run of beautiful weather. It's also incredibly quiet, which probably wouldn't have been the case with the existing duct configuration. Should also supply approx. 60% of our hot water.

    Unit is a 3 ton climate master tranquility 27 with a ground loop consisting of 3x 600' lines (300' out and back) buried in approx 200' trenches. Even though I was prepared for all the digging, you really don't appreciate the magnitude of it until you actually see it up close and personal. Wasn't really too big a deal with us as most of the lines were buried in our horse paddock with a feed and return line to the manifold trenched out from our house across the driveway to the paddock. Someone with a manicured lawn might have a different outlook. To me, it just means less mowing for a while.

    So I'll attach some of the during and after outside pics to this post and some interior pics to a reply.

    Scott

    Attached Files:

    Laszlo likes this.

    Helpful Sponsor Ads!





  2. sesmith

    sesmith Member

    Joined:
    Dec 11, 2009
    Messages:
    223
    Loc:
    Central NY
    Interior pics. Oil furnace before (you can see the feed lines for the geothermal through the foundation wall at the side of the furnace) and a couple of after pics.

    Attached Files:

  3. begreen

    begreen Mooderator Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    53,348
    Loc:
    South Puget Sound, WA
    Thanks for posting sesmith and congratulations on the new install. Tell us more. Is there supplemental heat or is this it? Can I ask what it cost for the project?
  4. SolarAndWood

    SolarAndWood Minister of Fire

    Joined:
    Feb 3, 2008
    Messages:
    6,771
    Loc:
    Syracuse NY
    Very nice. I have wondered if geo with a net meter PV setup might be the way to go. While I think about it, I will keep stuffing the steel box and try not to get hurt feeding it.
  5. Jack22

    Jack22 New Member

    Joined:
    Mar 10, 2011
    Messages:
    95
    Loc:
    Warren County, New Jersey
    Very cool stuff. I have always been interested in geothermal systems. Do you run water with antifreeze through the loop in a system like this?
  6. nate379

    nate379 Guest

    Can you explain a little how that works?
  7. maple1

    maple1 Minister of Fire

    Joined:
    Sep 15, 2011
    Messages:
    4,957
    Loc:
    Nova Scotia
    I've also been considering geothermal for our heating system overhaul, but think I have pretty well decided against it.

    Not sure what your costs were, but here I think it would be right around the $20k mark - plus any duct work or related heat distribution setups, and then having to re-do the landscaping. We've got a 2 story with all baseboard, so would have to basically put in a whole new heating system to go geo - new ductwork & all. We'd likely be at around $30k, maybe - with increased electricity bills to run it. The operating cost is something I'd like to get a better handle on before I completely rule it out - hopefully after this winter I'll have some decent info on that from a couple guys here who have gone geo. I'm thinking it would be at least an extra $100/month, likely closer to $200. If I don't do that, and put in a new wood/oil system (at around $10k), my total operating costs should be less than $50/month, that's mostly for DHW. Maybe even down to $20 by spending another $1500 or so for heat pump water heating, or even less if I can light a wood fire every week or so. With free wood, it's hard to justify the outlay for geothermal plus increase operating costs - although the easy turn key clean operation is certainly attractive. I'm thinking (hoping) by the time I'm not able to do the wood thing anymore, technology will have improved to where it won't hurt as much to move away from wood - until then I have pretty well decided to take advantage of the free wood thing as long as I am able.

    Keep the info coming, it is certainly useful & appreciated. Good luck & keep us posted.
  8. sesmith

    sesmith Member

    Joined:
    Dec 11, 2009
    Messages:
    223
    Loc:
    Central NY
    I'll try to do a quick reply to some of the questions. First to all the wood heaters...keep doing what you're doing. It would be hard to find a way to heat your house any cheaper, especially if you cut your own wood, although operating expense wise, not considering installation, the geo unit will cost less to run, in my area, than if I bought firewood. I'd still be heating with wood...in fact my wood supply that was designated for this year is still out in the woods cut and bucked where I left it. I was starting to look at alternatives anyhow. I thought that cutting and splitting the usual 6 cords might get old by the time I got to my 60's. I had a good run of cheap heat going, though.

    This system uses glycol in the coolant loop underground. The coolant comes in at around 52 degrees currently and leaves the unit at around 46 degrees (in 1 stage heat). That 6 degree temperature difference collected from the soil gets turned into about 90ish degrees (measured at my closest air duct to the unit). It does this first, by moving a lot of coolant through the ground loop, and then using a refrigerant loop in the unit, which boosts the temperature using the phase change properties of the refrigerant, much the same as a refrigerator takes the heat out of the inside of the refrigerator and puts it into your house. All this is done at about 400% efficiency, so for every 100 btu equivalent of electricity you use to run the unit, you get approx. 400 btu out in the way of heat. This is true when you are running on 1st stage heat. The compressor in the unit is is 2 stage, so if it needs to put out more heat than you get in stage 1, it will move on to stage 2, but be less efficient there. There is also an auxiliary electric resistance heater in the unit, that can be used to supply more heat, or be used as a backup if the unit breaks, but at a much higher cost of operation. The aux heat can be locked out by using the outside temperature sensor I have installed, so, for instance, you can program the tstat to prevent aux heat from coming on unless the the outside temperature is less than, say 20 degrees. This prevents aux heat from coming on if you were to bump the tstat up a few degrees and the unit attempted to raise room temperature quickly. Basically, everything in the tstat is programmable, so the system can be tweaked to be as efficient as possible minimizing stage 2 and aux heat while maintaining a set temperature in the house that is very stable. During the summer, the system can be run to remove heat from the house and put into the ground. AC is not important for us here, but there are times when it's nice. There's also a water heating circuit in the unit tied to a 60 gal storage tank that will supply up to 120 degree water at little cost.

    Cost of the unit was 24k. The federal tax credit will bring that down to 16k net. A huge amount of money for a heating system, but using $3.62/gal oil prices (which is conservative) and $0.12 kw hr electric rates (most recent bill was $0.116 including delivery, misc fees and taxes), the initial installation cost should come back to us in savings over oil heat within 7 years. It will also add some value to the house, though currently NY state cannot increase your tax assessment due to geo or solar energy installations (so the laws say, anyway). This is not even taking into consideration the aesthetics of having a clean heat source, less work, and much cleaner inside air quality in the house. Of course, the true picture will be obvious come Jan-Feb.

    I also still have my wood stove in case the power goes out...or if I miss it too much.
  9. sesmith

    sesmith Member

    Joined:
    Dec 11, 2009
    Messages:
    223
    Loc:
    Central NY
    Here's a link to a good xcel calculator from the EIA that may help you get a rough idea of your operating costs. It takes into consideration heating efficiency as well as combustion efficiency of the various heating options out there. You can fill in local costs of the fuels and adjust the efficiencies, if necessary, to match your equipment.

    http://www.eia.gov/neic/experts/heatcalc.xls
  10. nate379

    nate379 Guest

    Interesting setup!

    I'm not sure anyone has done it up here. The frost line is about 10 ft so it would require some deep trenching or maybe going straight down like a water well?
  11. sesmith

    sesmith Member

    Joined:
    Dec 11, 2009
    Messages:
    223
    Loc:
    Central NY
    Thanks.

    Here's an interesting (but long) read on geo in Alaska:

    http://www.google.com/url?sa=t&rct=...kZymAw&usg=AFQjCNF-5-QUACftRJ3Py0PmsQSXf_2_SQ

    A couple of quotes from it:

    "Alaska’s GSHP industry is small, but recently has shown growth, with some prominent commercial
    installations in Juneau and several residential installations in Fairbanks. One large-profile commercial
    GSHP system has recently been installed at the Juneau Airport Terminal. "

    "Residential GSHP owners interviewed for this report had installed a GSHP for a variety of reasons, but
    each homeowner reported that long-term cost savings was a strong motivation. Some homeowners
    found their systems to be low-maintenance, and more than one homeowner installed a GSHP in part
    because it is a partially renewable-energy technology. All of the residential GSHP owners interviewed
    reported satisfaction with their systems."

    "No drilling companies in Alaska were identified that can drill boreholes cheaply enough to compete with
    horizontal systems. The high cost is due to a combination of ground conditions, limited competition, and
    available equipment."
  12. semipro

    semipro Minister of Fire

    Joined:
    Jan 12, 2009
    Messages:
    2,572
    Loc:
    SW Virginia
    Nice system. You're going to love it, especially after you pass the break-even point.

    You mentioned that the duct system was quieter. Geo systems are nice too in that you have no noisy outside condenser unit.

    Too bad they can't figure out a less intrusive method for installing the heat exchange tubing underground. Maybe someone has. Our Geo is an open loop system that uses our drinking water well. I've considered converting to an in-ground loop system like yours.
  13. johnny1720

    johnny1720 Member

    Joined:
    Mar 6, 2007
    Messages:
    221
    Loc:
    The Great North East
    Can you give us an update on this?

    I just had a 4 ton ClimateMaster 27 series installed last friday.

    It is warmer in this house than it has ever been.
  14. sesmith

    sesmith Member

    Joined:
    Dec 11, 2009
    Messages:
    223
    Loc:
    Central NY
    Congrats. Saw your pics on the geo forum.

    Update on mine. It's been a warmer than average winter here in central NY, as you know. We have had a couple of below zero nights though, to test the system. It works just as it was designed. As the outside temp drops into the single digits, the heat pump will go into second stage operation. Usually, by the next morning, it will still be in second stage with the aux heat coming on periodically to help out, at those temps. The system was designed with a balance point of 7 degrees and an interior set point of 70 degrees. We like it at 67, so operation is right in line with it's design, maybe a little better. Right now, the incoming loop temp is around 38-39 degrees, so the loop is also working as designed (avg loop temp target was 40 with a minimum of 32). Best of all is my electric use. The geo system cost me about $35 to run for the month of Nov., about $65 to run for the month of Dec, and about $75 to run for the month of Jan (this is the electric use over my average, which was pretty consistent over the last year or so). Even if NYSEG managed to double my electric rate (which has been around 10-11 cents per kwh lately) it would still be a bargain to heat with. No complaints here. Better than spending 3k on oil, and I still haven't burned my wood stove this year, but the chimney's clean, just in case.
  15. Ehouse

    Ehouse Minister of Fire

    Joined:
    Jul 22, 2011
    Messages:
    906
    Loc:
    Upstate NY
    I have a system sitting on pallets in my garage waiting for the bucks to finish the house shell. It's a bit different so I'll describe it. This is a closed loop pond set up (8' depth is sufficient in central NY) with minimal excavation required, just 2 trenches from house to pond. The main heat pump unit is water to water and feeds high mass radiant floors throughout the house. It will handle about 3/4 of the heating load for the coldest expected temps. When this capacity is exceeded, a second unit, which is water to air kicks in for aux. heat. It is hooked up to the air handler containing an HRV and can also supply AC and DHW. The floor temps are projected to operate at 81 degrees F.

    Higher efficiencies are purportedly obtained with DX (direct exchange) where the refrigerant it's self runs in the collection tubing and cuts down on excavation in ground loops.


    Pricing is all over the place so shop around.

    Ehouse
  16. johnny1720

    johnny1720 Member

    Joined:
    Mar 6, 2007
    Messages:
    221
    Loc:
    The Great North East
    We have only been down to 17 degrees one night, I am actually really looking forward to a good cold snap. I want to see what this system will do. I only had my unit in stage 2 once, I had closed a damper in the same room as the thermostat, it was 75 in the rest of the house and only 70 in the room where the thermostat is located. That is encouraging to see such low numbers for heat cost. I know I will not be nearly as lucky as you, I expect to pay at least 200 each month in addition to the normal electric bill (during heating months)
  17. Jerry_NJ

    Jerry_NJ Minister of Fire

    Joined:
    Apr 19, 2008
    Messages:
    1,046
    Loc:
    New Jersey USA
    I've been running a 3 ton Water Furnace geo unit for close to 20 years. Interestingly the efficiencies seem to still be competitive. My unit delivers COP of 4 in low speed (the most efficient speed) and about 3.5 in high speed (that at 36K BTU output). I have a dual vertical loop which puts a lot of exchange in the water table. The COP of 3.5 is with a ground loop at 32 degrees, I think it has never been close to that cold. It was maintenance/repair free for about 15 years, I have since put about $3k into replacing some of the rotating machinery, the compressor has not been replaced.

    We are a bit higher on electricity cost at about 16 cents per KWH, but still the geo HP is lower cost heat than hardwood purchased at about $220 a cord. However, I use about two cords of wood a year, in part because I like it and in part when it is real cold I like to give the ground loop a rest to recover. When I have the wood insert going I keep the hp off for several hours, usually 10 to 12 hours. I believe that helps get the COP up a bit when the HP comes back on line.

    I think mine has paid for itself, but it was not more economical in than oil in its early years, here electricity was bout 10 cents a KWH and I think heating oil was about $1 a gallon. Heating oil has tripled in cost while electricity has gone up about 60%. I do worry however when ever I remember the threats I've heard "electric rates will necessarily sky rocket", but the fact that congress refused to pass the cap and trade has made the geo HP the most economical way to heat, cool too, it has an EER of about 20.

    I checked the Water Furnace web site and see they are advertising a COP of 5 in their best unit. I know there are a number of improvements in compressor design that my old unit does not have.
  18. sesmith

    sesmith Member

    Joined:
    Dec 11, 2009
    Messages:
    223
    Loc:
    Central NY
    FWIW, my numbers don't include the fact that the system offsets some of the water heating done by my electric water heater with the desuperheater, so the cost to run the geothermal has to be at least a little more. Still, as far as I'm concerned, the bottom line is how much more electricity I'm using at the end of the month total. Also, we have a small house that I've done a lot of energy upgrades to over the years, and we like it on the cool side. I think if it ever got up to 75 in the winter, I'd switch the thing over to "cool".

    It will be interesting to see how things work out when we get a real winter, but even so, I'm really impressed with the system. The fact that it keeps the house within a degree of the tstat set point, and all the downstairs rooms are within a degree of each other in this old house is amazing. 67 with this system feels fine while 67 with the old oil furnace felt cold, but we rarely set it any higher because of the cost of oil, and set it way back at night and in the day when we weren't home. When heating with wood, my kitchen area was usually 70ish and my living room probably more like 65. so we feel spoiled this year. I know what you mean when you say your house has never been warmer. Strangely, the hardest thing we have had to get used to is that we really do like it even cooler for sleeping and it's been almost too warm. I tried a 1 or 2 degree setback earlier in the year, but found that as the weather got colder, the system works pretty hard to bring the house back up to temperature. Didn't seem worth the trouble, so we just leave it set at one temperature and close off our bed room registers at night. Actually kind of a hard thing to get used to as the setback thing is so ingrained from many years of doing it, and wood heat sets itself back by morning, especially if you oversleep. The geo heat also doesn't dry the house out like the other heat sources we had, and the system really does a good job of filtering the air in the house. I'm sure you'll like yours.
  19. sesmith

    sesmith Member

    Joined:
    Dec 11, 2009
    Messages:
    223
    Loc:
    Central NY
    Jerry,

    Glad to hear of a 20 year old system that's been pretty trouble free. 3k over 20 years is probably less than you'd spend on routine maintenance on an oil furnace over that time, not including repairs, and the oil furnace would be getting close to replacement time. That's really the only unknown at this point. Hope I have as good luck with mine.

    Your picture of Montana reminds me of my 12 year old golden who is laying down next to me right now. He's showing the white face yours had in the pic and doesn't move as fast as he used to, but neither do I. Good dogs age too fast.
  20. sesmith

    sesmith Member

    Joined:
    Dec 11, 2009
    Messages:
    223
    Loc:
    Central NY
    Sounds like an interesting setup.

    I'm not so sure of the higher efficiency claims of the DX systems, but I'm certainly no expert. It seems to me that you're only going to get so much heat out of an area of ground, so the fact that they use smaller loops just means they have to operate at lower temps so they have to be a little more efficient to pull that off. So a ground loop water to air (non-DX) just has to pull the heat from a larger loop. Big deal?? Either way, I wonder if operating costs are really any different at the end of the year. Personally, I'd rather keep the freon circuit in the house. Seems likely to be more trouble free that way, but I'm sure the DX fans would see it differently.
  21. Ehouse

    Ehouse Minister of Fire

    Joined:
    Jul 22, 2011
    Messages:
    906
    Loc:
    Upstate NY
    I'm unsure of the claimed efficiencies of DX also, but semipro, I think, was asking about improved ground loops. I think the refrigerant has to go in copper lines for DX. Using slinky or coiled loops is another option but may also run into the problem of over taxing the ground collection area. I think it is less of a problem for pond or open well loops as the moving water can more readily recharge the collection area. When I was figuring out my system I was thinking of using the area beneath the house ( vertical boreholes with slinky loops) to utilize the foundation excavation. The rough calculations I did indicated this would work, and I intended to run a couple of extra lines outside the footer for good measure. Aside from the space and excavation saving aspect if this kind of install, the house itself would insulate the collection area allowing it to recharge faster. I got some negative feedback from Professionals helping me with the design who said this had been tried in Sweden with poor results, but that's Sweden. I think it could be designed to work in a more favorable clime. Unfortunately, (or not) I ran into bedrock just below my footer, and the pond was handy, so I followed the POLR. This is all important emerging technology and it's good to hear people's experiences with their installs, good and bad. Any one have a DX loop?

    Ehouse
  22. DickRussell

    DickRussell Burning Hunk

    Joined:
    Mar 1, 2011
    Messages:
    143
    Loc:
    central NH
    In any GSHP system, there is a heat exchange system on the ground end. Heat is transferred between the ground and whatever fluid is circulated between the heat pump and the ground loop. Usually the fluid is water, perhaps with glycol in it for freeze protection, but in a DX system the fluid is the refrigerant itself. In almost any heat exchanger, there are three separate heat transfer coefficients. There is one for the fluid being circulated (call it Uf). There is another for the ground itself (call this Ug). If there is a tube wall (plastic or copper) through which the fluid flows, there is a third coefficient for heat transfer through the tube wall (call it Uw). This third coefficient is absent for a Standing Column Well (SCW) design, in which well water circulating between the heat pump and the well is in direct contact with the well bore. The overall heat transfer coefficient (U) is calculated from:

    1/U = 1/Uf + 1/Ug + 1/Uw

    The value of Uf depends on the fluid properties, its velocity through the tube, and the tube diameter. The value of Ug depends on the thermal conductivity of the ground material and in the case of packed soil is strongly affected by both how wet it is and how tightly packed around the tube it is. The value of Uw is calculated directly from the thermal conductivity of the tube material.

    In a DX system, the vaporizing or condensing refrigerant has a very high heat transfer coefficient, relative to that of a flowing liquid. Furthermore, in a DX system, there is no need for a heat exchanger in the inside portion of the overall loop to transfer heat between refrigerant and circulating fluid, because the refrigerant IS the circulating fluid. Also, the tube in a DX system, being copper, is far more conductive than plastic, so that Uw is much higher. Both Uf and Uw being much higher in a DX system tend to make the length of tubing that much shorter.

    Then we come to the heat capacity of the chunk of ground in contact with the copper tube and the comments by Ehouse regarding overtaxing the ground collection area. It may be one thing to have a shorter coil in a DX system, [edit: due to] higher overall heat transfer coefficient. After all, the heat transfer rate is given by Q = U*A*dT, where A is the tube area and dT is the temperature difference. Initially there will be a higher rate of heat transfer, but removing heat from the ground next to the tube depresses the ground temperature in heating mode or raises it in cooling mode. The temperature difference drops accordingly, and that reduces the heat transfer rate. As the temperature of the ground next to the tube goes up or down, heat is transferred to it from the surrounding soil. Given a long enough run time, some quasi equilibrium point would be reached, which ultimately determines overall heat transfer rate and thus the system capacity. Hopefully there is enough ground in the vicinity of the tube to provide heat through the heating season.

    Even though a DX system ought to need much less tube length, due to the higher overall heat transfer coefficient, success of the design does depend either on having enough mass of ground in the immediate vicinity of the tube (perhaps enough tube length) or on the existence of a different mechanism for bringing heat back to the ground around the tube. Having the copper tube in a drilled hole in rock is better than having it in dry sand, obviously, owing to the much higher conductivity of solid rock. If the tube is in a flowing aquifer layer, the flow of water past the tube (even if the flow is slow through a soil layer) takes care of the heat recharge issue. Without such a recharge mechanism, not dependent on slow conduction of heat through the ground, the copper tube may have to be a lot closer in length to what would be required for water through a black plastic slinky to gain access to enough heat for the long haul. In that case, the volume of refrigerant needed to charge the loop may be prohibitive. There is no one size fits all solution. DX can be a good solution for the right physical situation. It's not best for all situations.
  23. Ehouse

    Ehouse Minister of Fire

    Joined:
    Jul 22, 2011
    Messages:
    906
    Loc:
    Upstate NY
    Thanx for that!

    So for a ground loop with no special recharging capabilities, DX will require less tubing if spaced correctly, but draw no more heat from a given collection field, eh?

    What might happen if you placed a DX loop in a spring out flow or the tail wash tube from a pond stand pipe, say after a micro hydro turbine in the drop tube? Or a silo or ensilage bunker or a manure pit?

    Ehouse
  24. Jerry_NJ

    Jerry_NJ Minister of Fire

    Joined:
    Apr 19, 2008
    Messages:
    1,046
    Loc:
    New Jersey USA
    One of the reasons, no equations written or calculations made, I use my airtight wood insert to heat is to give the "ground" look time to recover. I intuitively concluded that on real cold weather when the HP is running at least 60% of the time, making it shut down for 10 to 12 hours by using wood to heat helps the loop recover. These wood heat run are mostly after dark, when we have lost the benefits of solar heating. That said, have a wood fire too because I enjoy the sight and feel of it, albeit that requires I'm neat the fireplace insert. My HP is efficient enough that it gives me more BTU/$ than does wood, and it heats the whole house to a near equal temperature. The HP does have a low speed fan setting which I leave on 24/7, and that helps some with distributing the heat. Having a two story home (not large, about 2,000 sq ft) with a central open staircase, and large door (arches) between the living room's fireplace also help move the warmed air around.

    The discussion above suggests my goal of giving the ground loop time to recover is reasonable. I have two vertical loops and that extend well into the aquifer from which we pump our drinking/house water, so I know the loop benefits from the water table, perhaps enough that my recovery strategy is of no benefit. I enjoy the wood fire anyway, and at least when I have it fired up the HP is off other than the circulation fan.
  25. sesmith

    sesmith Member

    Joined:
    Dec 11, 2009
    Messages:
    223
    Loc:
    Central NY

Share This Page