About Geothermal Energy


What is Geothermal Energy?

Geothermal energy is solar energy stored in the earth's crust. Geothermal energy is also considered as energy from Magma and the radioactive decay of uranium, thorium and potassium.

How does a Geothermal Heat Pump Work?

A geothermal heat pump transfers heat from one place to another by evaporating & condensing refrigerant using a compressor and an expansion device.

In the heating mode, we have a coaxial heat exchanger that acts as the evaporator coil in which we take heat out of the water flowing through it. Then this refrigerant enters the compressor. The compressor boosts the pressure & temperature of the refrigerant Now this high evaporated temperature crosses through the Condenser heat exchanger. Here the air temperature in the home is cooler than the refrigerant temp. Therefore the refrigerant temp gives it's heat up to the air, condensing back into a liquid. This high pressure liquid is then pushed through a small expansion valve device. This device changes the characteristics of the refrigerant to a saturated cool gas because of the massive pressure drop. Where the temperature now is cooler than the column of water flowing through it it can again extract heat from the water and continue this process.

In the cooling mode this process reverses. A reversing valve activates and changes the flow of refrigerant through the system. Now the Condenser becomes the evaporator and the evaporator becomes the condenser. Still the same process takes place.

What are the different Types of Geothermal Heat Pumps?

There are two types of geothermal Heat Pumps.
          ● Water to Air
          ● Water to Water

Water to air heat pump utilize a ducted system in which heating or cooling is distributed.

Water to Water systems have a secondary heat exchanger. This system is used for hydronics or radiant heat.

High temperature circuits such as baseboard, radiators are not recommended for they require very high water temperature. A heat pump will provide a max water temp of 120 degrees, unlike a boiler that will heat to 180 degrees.

What to think about when considering Geothermal Air
          ● Is the structure single story or two story
          ● Is there a full basement with at least an 8' ceiling
          ● If there is a second floor, is there attic space available
          ● Simply need space for Ductwork.

What to think about when considering Geothermal Radiant

Radiant in Lightweight concrete:
          ● Structural Support, sizing of floor joists
          ● Partition plates, may want to double them depending on thickness.
          ● Plumbing rough in.
          ● Electrical rough in.
          ● Island base
          ● Floor coverings
          ● Jack & header heights

If you choose not to use concrete
          ● Staple up systems can be done, (supplemental heat required)
          ● Panelized systems can be done. (expensive)

Geothermal Related

There are many things that go along with a geothermal system.
          ● Tonnage
          ● Single or Two Stage Compressor
          ● Single Speed or Variable Speed Blower
          ● Desuperheater and options
          ● Well Control & bleed
          ● Duct Sizing
          ● Radiant Manifolds
          ● Water temperature
          ● Noise
          ● Refrigerant type
          ● Diagnostics
          ● Outdoor controls
          ● Solar Option

Emergency Heat

Any type of Heating System can fail, including Geothermal. Living in Maine, it is a good idea to have a backup regardless of what type of heating system you have. That is why we install a system that has a backup.

          ● Water to Air System- electric duct heater backup
          ● Water to Water System- electric backup in Accumulator tank.

Generator Related
Generators can be used. Just note that the generator needs to be sized for the start up Amp draw or the inrush Amps. This is typically 3 times the running load amps. Unfortunately we need to size the generator for this 1 or 2 second demand to get the compressor operational.

Equipment Sizing
Sizing a geothermal system is very much the same as a conventional system.

          ● Floor Plans & Elevations required, sometimes cross sections
          ● Insulation Type and R-value
          ● Window sizes
          ● orientation (more for cooling)
          ● internal loads (commercial only)

Electrician Related
          ● Electrician needs to know loads for their proper sizing
          ● They need to be aware of the grounding practices
          ● It's best to have electrician contact us for this information

Construction Process
Construction process is very similar to conventional heating systems
          ● First Step should be to have the well drilled
          ● Once the roof is liquid tight we can begin
          ● Windows not needed but should have plastic if near mechanicals
          ● Water to air system it is not recommended to run under construction
          ● Radiant systems can operate sooner. Building should be insulated.

Tax Incentives and Federal Credits for Geothermal Energy Systems
          ● $ 2,000.00 renewable energy tax credit for systems installed between Jan. 1st 2008 and Dec. 31st 2016.
          ● Income tax credit $ 300.00 year.
          ● There is a 30% TAX CREDIT WITH NO CAP!!!!

Visit our Tax Credit page

To learn more on how a geothermal system can benefit your home or business, please contact us via email or phone us at 207-647-8782.

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Gagnon Heating & Air Conditioning, Inc.
Route 302, Bridgton, Maine
Phone: 207-647-8782, Cell: 207-632-3239
GPS Address: 14 Seymour Drive, Bridgton, Maine
Mailing Address: PO Box 814, Bridgton, ME 04009