Advanced GeoThermal Concepts
Ground Source Heat Pumps

This introduction to GSHP is done in the form of questions and answers. This material is Copyrighted by IGSHPA and has been used with their permission.  It has also been modified when necessary and appropriate changes have been made so that generic answers would apply to the specifics of Yavapai Plumbing & Heating, The State of Arizona, public utilities like APS, etc.

How does a GSHP system heat water for my home?

Using what is called a desuperheater; GSHPs turn waste heat to the task of heating hot water. During the summer, when the system is in cooling mode, your hot water is produced free as a byproduct of the thermal process. In winter, with the heating mode, the desuperheater heats a portion of your hot water. Desuperheaters are standard on some units, optional on others. Stand-alone systems that will heat water all year around can be purchased. YP&H strongly recommends that one takes advantage of this feature, because for a very small investment you will save significantly on heating your domestic hot water.

How effective is this underground system?

The buried pipe, or ground loop, is the most recent technical advancement in heat pump technology. Recently, new heat pump designs and improved buried pipe materials have been combined to make GSHP systems the most efficient heating and cooling systems available.

Are GSHP systems guaranteed?

Nearly all GSHP system manufacturers offer a warranty for major components that is equivalent to the warranties for conventional heating and cooling systems. Manufacturers of plastic pipe used for ground loops warrant their products for 50 years.

Can these systems be used for commercial, industrial, or apartment requirements?

Yes! Many GSHP systems are being installed using a multitude of systems hooked up to an array of buried vertical or horizontal loops. This simplifies zone control and internal load balancing.

How would increased use of GSHP systems affect electricity cost and availability?

The reduced peak load requirements would allow utilities to serve more customers and to lower fixed costs per customer, thus offsetting some increased variable costs. This would result in less cost per kilowatt, since fixed investment for new capacity is high.

Can I install a ground source heat exchanger myself?

It’s not recommended. Thermal fusion of the pipe, drilling and trenching are procedures best handled by licensed professionals. Nonprofessional installations may result in less than optimum performance, which could cancel out anticipated savings.  In the state of Arizona and APS the largest electricity supplier in the state it is strongly recommended that you have an IGSHPA Accredited Installer involved with any GeoThermal installation.  YP&H does have and IGSHPA Accredited Installer on their staff.

How far apart are trenches and vertical boreholes spaced?

Trenches are spaced four to five feet apart while boreholes are spaced ten to fifteen feet apart.

How long does it take to install a horizontal system?

This depends on soil conditions, length and depth of pipe, and equipment required. A typical installation can be completed in 10 or 14 days.

How long does it take to install a vertical system?

With the vertical installation, time varies with conditions on the site such as type and depth of the overburden, type and hardness of the bedrock, and the presence of aquifers. Typical drilling times per hole are one or two days; total installation can usually be accomplished over a two week period.

Is it advisable to install a GSHP system large enough to handle my total heating needs?

GSHP systems are generally sized to meet all your cooling needs. Depending on heating needs, a GSHP system usually supplies 80-100 percent of your design heating load. Sizing the system to handle your entire heating needs may result in slightly lower heating costs, but the savings may not offset the added total of the larger system. YP&H will perform a complete heating and cooling load calculation for your entire home to help assure the correct equipment selection is made.

What are the environmental benefits of GSHP systems?

Currently installed systems are making a huge difference in our environment! The systems are eliminating more than three million tons of carbon dioxide and are equivalent of taking 650,000 automobiles off the road. GSHP systems conserve energy and, because they move heat that already exist rather than burning something to create heat; they reduce the amount of toxic emissions in the atmosphere. They use renewable energy, and because the system doesn’t rely on outside air, it keeps the air inside of buildings cleaner and free from pollens, outdoor pollutants, mold spores, and other allergens.

Can a GSHP system be added to my fossil fuel furnace?

Yes. Called dual systems, they can easily be added to existing furnaces for those wishing to have a dual-fuel heating system. Dual-fuel systems use the GSHP system as the main heating source, and a fossil fuel furnace as a supplement in extremely cold weather should additional heat be needed.

Will I have to add insulation to my home if I install one of these systems?

Ground source heat pump systems will reduce your heating and cooling costs regardless of how well your home is insulated. However, insulating and weatherizing are key factors in gaining the maximum amount of savings from any type of heating and cooling system.

Some of this material was taken and modified to be applicable to local conditions and issues.
Credit and Copyright © 2010 IGSHPA (International Ground Source Heat Pump Association)

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