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Geothermal - Put your excavator to good use!

Discussion in 'Heavy Equipment & Pavement' started by BobcatSteve, Jan 28, 2008.

  1. BobcatSteve

    BobcatSteve LawnSite Member
    Posts: 8

    Make a difference while making a profit!
    Many of you on this part of the forum have the equipment and skills to add a new service to your business while also helping to conserve energy and the environment.

    Geothermal ground loops can be installed using track excavators and loaders, and are an excellent system to save up to 60% on heating and air conditioning bills. More information can be found at the Geothermal Heat Pump Consortium - www.geoexchange.us. Some ground loops are installed vertically with well drilling equipment, while others can be installed in a horizontal configuration which is more cost effective and therefore frequently the preferred installation. Obviously, many here on this forum can be involved and profit in this endeavor with equipment that they already own. A search for geothermal contractors or engineers in your area will probably turn up a nice source of work for yourselves. There are already over one million geoexchange systems installed in the United States, so this is no longer a fringe technology.

    There is not a single person I know who wouldn't want to save 60% on their heating and air conditioning bills. Geothermal energy is both energy efficient and environmentally friendly and will become more and more popular as traditional fuel prices maintain their upward trend. Many states already have generous rebates, some as high as $600 per ton, for new geothermal systems.

    Below is a photo of a ground loop we recently installed in New Jersey. This system is 7 tons and required 3600 feet of piping in the ground. It can provide heating, air conditioning, and hot water at significant savings of approximately 60%. The trenches were seven to eight feet deep and about 42" wide. A hydraulic screener was used to sift away the stones to keep them off of the ground loop without needing to buy any sand. Note the smooth trench bottom despite the rock vein in the middle of the photo. The HDPE piping will last for over 100 years, so a little extra precaution is well worth the effort.
    Geothermal - A smart investment that is good for the country and great for the environment!

  2. Dirt Digger2

    Dirt Digger2 LawnSite Silver Member
    from PA
    Posts: 2,396

    we dig a lot of geo-thermal trenches for a well drilling company around here...not really that profitable...not really a whole lot of digging involved for a "typical" field
  3. Az Gardener

    Az Gardener LawnSite Gold Member
    Posts: 3,899

    Thank you for the link. We are designing a new home now and want to use geothermal but no one in Az does it.. I have contacted a accredited designer in Ca. and she wants 2500 just for the design. So I am looking for other options for the design part.

    We will be doing the install ourselves, my father in law is an old Colorado farmer and HVAC guy so he thinks he knows what needs to be done but we would like some confirmation.

    That part is kind of on the back burner for now as we are dealing with setbacks, variances and slow draftsmen. But I will probably contact you later to "pick your brain".
  4. Construct'O

    Construct'O LawnSite Bronze Member
    from Sw Iowa
    Posts: 1,387

    There is a guy i know that does this with a core drill and does it the vertical way.One of the reason this is used is when you don't have a big area to work in.Doesn't take much room going straight down.I think he usually drills three holes.

    Uses a backhoe and it core drill mounted on a truck,plus his supply truck.

    He keeps busy ,especially with the high price of heating fuel.I would consider this if i was building now days.I would do the horzinal with my own equipment and having enough room to install.

    Last time i visited with him,he did say that now the state is trying to get it passed to be certified and having to get permits ,since he gets into under ground water table the way he is doing it.

    Nice tip for someone wanting to expand there work options.
  5. AWJ Services

    AWJ Services LawnSite Platinum Member
    from Ga
    Posts: 4,276

    Most Geothermal equipment is 3 to 5 times that of conventional Heat pumps with the 60% savings not an accurate number over the new high seer conventional equipment.
    The equipment should be less price due to fact that it is easier to build with less components.
    The pump that runs the ground loop can and do fail regularly in my area with the high loads put on the ac/cooling units.the pumps are rather pricey too and if swayed from the geothermal units speccs any damage to the unit from an inferior pump will void the warranty.

    An average 3 ton heat pump installed here is around 4000 dollars.
    A geo thermal will run 12 to 15 k.

    They also rate the Heat pump and the Geo thermal in 2 different specs to further confuse the consumer.

    Modern heat pumps are pushing 14 +seer ratings and most geo thermals overall will only get in the high teens seer ratings.
    Expect 20 to 30 % savings.
    The Ground loop is tough to engineer in some areas to get rated efficiencies.

    On an average electric bill of 200 a month in can take upwards of 15 + years to recoup the savings.
  6. bobcat_ron

    bobcat_ron LawnSite Fanatic
    Posts: 10,101

    I've only done one, 3 big woven "balls" and back filled with sand. It's cheaper in the long run in our region.
  7. Dirt Digger2

    Dirt Digger2 LawnSite Silver Member
    from PA
    Posts: 2,396

    i understand how it cools the water but what i don't understand is how you can get heat out of the ground unless you are drilling way way down...in which case i dont see how the savings cost can overshadow the initial cost...someone enlighten me please
  8. RockSet N' Grade

    RockSet N' Grade LawnSite Silver Member
    Posts: 2,454

    Someone will correct me if I am wrong, but my general understanding is this. At a ground depth of 10-12', the earth remains a constant temp of around 52 degrees. This is the "heat source" you are tapping into. So, your fluid encased in piping picks up this temp and transfers it back. So now you have air coming back into the house of 52 degrees and it costs less to heat that or cool that in your environment vs. the outside air temp (which in our area varies from 108 in summer to -15 in the winter).
  9. RockSet N' Grade

    RockSet N' Grade LawnSite Silver Member
    Posts: 2,454

    Another thing I have found in my research on geothermal is that a good designer can "tweek" a standard geo system with the use of a passive solar collector (for heating) and increase the efficiency of the system another 20% on the heat side.
  10. BobcatSteve

    BobcatSteve LawnSite Member
    Posts: 8

    Lots of good questions and points.

    Az - It would be a good idea to know that your design is going to work before you start digging. On a new home, geo is a good way to go. In New Jersey, horizontal closed loop systems do not fall under the State's well drilling regulations like vertical bores do because they do not go through several layers of aquifers. It is important for the system to be designed properly as there are many engineering factors that are taken into consideration such as characteristics of the soil such as specific heat and moisture content, heat loss rates of the structure, friction losses, water velocity through the loop field, pump curve characteristics, and proper equipment sizing to name a few.

    Dirt digger - The geothermal system extracts heat from the constant ground temperature in the same way that your refrigerator/ freezer extracts heat from inside the cold box and blows that heat out the back. The ground does not need to be hotter than 55 degrees to for the system to blow 100 degree hot air. Even though the ground is 55 degrees, there is still heat to be extracted as the loop fluid will leave the geothermal unit at a lower temperature than it was when it entered it. It then warms up in the loop field and returns to the unit for more heat extraction. This process continues all winter. A compressor, condenser, and evaporator are used with a refrigerant that has a low boiling point. When mater undergoes a phase change from liquid to gas (or liquid to solid), latent heat energy is absorbed or released to effect that phase change, and is the principal behind modern refrigerators and heat pumps. A geothermal unit has a reversing valve that can reverse the direction of flow and allow it to heat and cool.

    Horizontal loops will provide plenty of earth moving for an excavating company on every installation.

    Awj - Of course it is going to cost more for the first cost, but that is the price one will pay to have a steady cash flow (savings) on their investment. After an initial investment, you will see a return every year. Geothermal systems are typically more cost effective on larger installations, though they will still provide a decent return to the owner on a properly designed smaller system. Your efficiencies are incorrect: An 038 unit by waterfurnace can achieve an efficiency rating of 30 SEER, and many of their units have seer ratings in the 20 to 25 range. Their specifications are here. Smaller units tend to be more efficient than larger units. An older central air conditioner can have a seer rating of only 10 or 12 for comparison. On the heating side, a properly designed ground loop will always out perform an air to air heat exchanger as the incoming loop temperature will be higher than the ambient air, and cause the efficiency to be increased.

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