ABM Mechanical, Inc. Mechanical Contractor, Plumbing, HVAC & Electric Systems Contractor. Located in Bangor, Westbrook, Hancock, Maine.

How Does Geothermal Energy Work?

Geothermal energy is defined as heat contained within the Earth. The upper layer of the earth’s soil maintains a relatively constant temperature despite the season. The temperature of the ground is warmer than the outside air during the winter months and cooler during the summer months. A geothermal heat pump is able to use this temperature difference to provide essentially free heating and cooling. Typical geothermal systems utilize the upper layer of the earth’s soil as a heat exchanger. In geothermal terms this heat exchanger is called a bore field loop, or a system of pipes buried in the shallow earth. A fluid is circulated through this loop to provide a method of heat transfer, either to reject heat during summer cooling mode or to draw heat in during winter heating mode.

Reduced Operating Costs

A geothermal system does not create the energy used for heating or cooling as in a conventional system but simply provides a method of transferring this energy in a useful manner from the ground to the system. Because of this feature, a geothermal system is much less expensive to operate than a conventional heating or cooling system. Roughly 75% of geothermal energy is free and therefore a system can see a simple payback of capital costs in less than 5 years.

Reduced Maintenance Costs

Geothermal systems last longer: 25 years for the mechanical equipment and 50+ years for the ground loops, compared to 15 to 20 year life expectancy for traditional HVAC equipment. With zero combustion, there is little requirement for an annual service or need for a mechanical maintenance staff) on your payroll. 50% of the mechanical system is now buried in the ground.(The loop should be monitored for temperature and pressure. Air filters need to be cleaned or changed regularly.)

Increased Safety

Geothermal equipment is installed indoors. This improves longevity of equipment and provides a safe environment for maintenance staff. Workers are not exposed to the dangers of servicing equipment on rooftops. Because combustion is eliminated, there is no production of carbon monoxide from a geothermal system.

Improved Indoor Comfort

Multi-stage units that do not overheat or overcool provide a very consistent temperature throughout the building. 100% dehumidification can be added to most systems, fanspeed dehum control is built in to all units with ECM fan motors. Both systems provide the client with optimum humidity control and increased comfort. These systems are easily matched to energy recovery ventilation for efficient use of fresh outdoor air. Classroom units have energy recovery built-in.

Improved Indoor Air Quality

Most systems can be tied directly to any fresh air ventilation system when energy recovery is utilitzed. Classroom units have built in ERV heatwheels. Fresh air is controlled through an internal CO2 and occupancy sensor for optimum efficiency.

Corporate Image

Building owners can now showcase their commitment to environmental responsibility through the use of sustainable and renewable energy. ABM Mechanical, Inc. can assist you with delivering that message to the local community.

Additional Advantages

No outdoor condensing units or cooling towers on roof or ground provide architectural freedom and less structural concerns from weight of roof-top equipment.

Reduced Overall GHG Emissions Including Zero On-Site Emissions

Geothermal heat pumps produce no GHG emissions on site. Due to the high efficiency and reduced use of electricity, geothermal heat pumps also produce less GHG emissions from offsite sources.

Tax Incentives

New Construction Example with 50% Bonus Depreciation:

A corporation spends $1,000,000 to install a geothermal heat pump system in its new office building. They moved into the building during the 4th quarter of 2010. The corporation is in a 40% tax bracket when state income tax is included.

2012 Tax Credit: $1,000,000 x 10% = $100,000
Depreciable Basis: $1,000,000 – ($100,000 / 2) = $950,000
2012 Tax Credit:$1,000,000 x 10% = $100,000
2012 Bonus Tax Benefit: $950,000 x 50% bonus x 40% tax rate = $190,000
2012 MACRS Tax Benefit: $475,000 x 5% Q4 MACRS x 40% tax rate = $9,500
2012 $475,000 x 38% MACRS x 40% tax rate = $72,200
2013 $475,000 x 22.80% MACRS x 40% tax rate = $43,320
2014 $475,000 x 13.68% MACRS x 40% tax rate = $25,992
2015 $475,000 x 10.94% MACRS x 40% tax rate = $20,786
2016 $475,000 x 9.58% MACRS x 40% tax rate = $18,202
Total Tax Savings over 5 Years: $480,000

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Geothermal Heating

& Air Conditioning Systems