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This file contains information on three types of systems:

  • Water based geothermal systems
  • Underground copper tubes carrying a refrigerant
  • Undergound pvc tubes cooled and heated by solar energy

Geothermal Heating And Cooling

Klaus Kolb installed a Water Furnace Geothermal Heat Pump (a two ton Premier Model PO22TL101NADSSA) with a 1/2 HP Blower and a 1/2 HP Loop Pump in his South Carolina 40' American Ingenuity Dome Home. In retrospect he realizes the 40' dome needed only a 1.5 ton unit.

Klaus stated, "I buried two loops of 500' each, 1/2" special plastic pipe by Water Furnace in a 2' wide ditch 6' deep in my pasture. At that depth and in our latitude, there is a constant temperature of 59 degree F (free buried sun energy). My heat pump uses this base temperature to either heat my home dome in winter to 70 degrees or cool in summer to 75 degrees. Thus my delta T (temperature differential) is very small, resulting in minimal energy consumption."

Klaus's 2003 total monthly average energy bill was $49. This includes the electricity and propane costs for his entire 1,600 sq.ft. dome. Some of the features of Klaus's 40' dome are:

  1. The dome's insulation was Ai's standard R-28 insulation (seven inch thick E.P.S. which is comparable to eleven inches of fiberglas batting).
  2. The tankless water heater used propane as the fuel. Klaus installed a Rinnai Continuum tankless (Troughflow) water heater. The specifications were: Whole House Unit Model REU 2424W-US; Min 19000 BTU, Max 180000 BTU; LP Gas.
  3. Geothermal cooling pipes were installed.
  4. The washing machine is an Energy Star which means it uses one half the water and one half the electricity of a standard washing machine.
  5. Compact fluorescents were used through out the dome. 17 watts gives 60 watts of light; 27 watts gives 100 watts of light.


These photos show Klaus Kolb installing the plastic pipe.


The following article was taken from the Summer 2009 Butte Environmental Council’s (BEC) News.   The geodesic dome home was built from American Ingenuity dome building kits.  BEC is a not-for-profit public benefit corporation.  Founded in 1975, BEC protects the land, air, and water of Butte County California through advocacy, environmental education, and information and referral services.  To view photos of the Kaufman dome home, click on Green Home.

ChicoEco Highlights a Geodesic Dome Home

By Nani Teves

Hidden among the trees in the mountain community of Forest Ranch is the most amazing example of living more responsibly by combining conservation and cutting edge.  Ron Kaufman and Marti Leicester spent four years planning and 14 months building their geothermally heated and cooled, concrete geodesic dome home, which, when all was said and done was approximately the same cost as building a traditional house of the same size.

A geodesic dome looks like the top half of a soccer ball, and theirs is two domes connected by a 12 ft length.  They used concrete as a building material because it is low maintenance, highly insulated, insect resistant, and most importantly for their area – fire resistant.  They built to optimize passive solar potential, used double pane windows and included 10 skylights that reduce the need for indoor lighting.

Throughout the house, renewable and reused building materials were used including the floor, which is made from Marmoleum, a durable linoleum made from linseed oil, jute and rosin.  For carpeted areas, 1ft by 2ft squares were used, making it possible to replace only damage areas.  Framing studs were reused to build the loft, the kitchen cabinets are bamboo and the stairs, window seats and baseboards are all make from a material called Evergrain, which consists of 50% HDPE (typically recycled milk bottles) and 50% wood fibers (typically old pallets).

One of the mot fascinating things about this house is that it uses geothermal energy for heating and cooling.  The system was expensive but they wanted to push the technology forward by experimenting.  How the system works is heat is collected from the dome interior and then pumped into the ground during cooling, and reversed during heating.  They hired an out of state company (no one was available locally or even in California) to drill four 180ft deep holes.  Crystal Air in Weaverville installed the system by placing tubing surrounded by Bentonite in the holes.  A two-way pump is run using energy from PG&E and a back-up generator, and the extra heat from this system is used to preheat the water for their on-demand tankless water heater.

Another unique feature they included in the design is a Heat Recovery Ventilator (HRV) System.  The HRV brings in fresh air and exhausts stale air, while transferring a significant portion of the heat in the stale air to the incoming fresh air.  It also maintains a slightly positive air pressure in the dome so that pollen and dust are not drawn in through open doors and windows.

From the jars reused to hold screws, to the dome itself, this house is an example of how fun it can be to research, experiment and live outside the box.

If you want to learn more, see photos, or contact Ron and Marti go to  is a Butte Environmental Council website that pulls together our communal knowledge of eco-projects, a directory of green businesses, and a full calendar of action events for the purpose of global cooling.

To research GeoThermal Heating and Cooling Systems visit Water Furnace's web site.

Water Furnace:

To research their web site, click on Water Furnace. The following info came directly from their web site.

What's a "Water Furnace"? Water Furnace is a pioneer and industry leader in the development and manufacture of geothermal heating and cooling systems. We don't just make them. We "practice what we preach"—by heating and cooling our Fort Wayne, Indiana, headquarters with our own WaterFurnace geothermal units. After all, we could hardly expect you to believe this technology is "Smarter from the Ground Up" if we weren't convinced of it ourselves.

Our entire Fort Wayne complex serves as a working model for large-scale industrial and commercial buildings across the country. It uses what's called a "closed loop" system spread over the bottom of a pond as its heating and cooling source. Sound remarkable? It is. Yet the science behind it is sound. We'll explain it to you.

Geothermal Heat Pumps

Key Product Criteria

Equipment Specification

Geothermal Heat Pumps

  • Open Loop: >=3.6 COP (H); >=16.2 EER (C)*
  • Closed Loop: >=3.3 COP (H); >=14.1 EER (C)*
  • Direct Expansion (DX): >=3.5 COP (H); >=15 EER (C)*
Product Type
Water Heating
Closed Loop
With integrated WH
Open Loop
With integrated WH
With integrated WH

Geothermal Heat Pump:

A geothermal heat pump model uses the thermal energy of the ground or groundwater as the heat source and heat sink for residential space heating and/or cooling. It may provide both space heating and cooling, cooling only or heating only functions. A geothermal heat pump model consists of one or more factory-made assemblies that normally include an indoor conditioning coil with air moving means, compressor(s) and refrigerant to fluid heat exchanger(s).

In addition, some or all of the domestic water heating shall be provided through the use of a desuperheater, integrated demand water heater or a separately installed compressor that provides demand water heating. The geothermal heat pump includes all the equipment and connections from the point at which the ground heat exchanger enters the house, except for indoor equipment that was installed by someone not representing the manufacturer or manufacturer's representative, such as the ground heat exchanger installer.

Closed Loop System:

A ground heat exchanger in which the heat transfer fluid is permanently contained in a closed system.

Open Loop System:

A ground heat exchanger in which the heat transfer fluid is part of a larger environment. The most common open loop systems use ground water or surface water as the heat transfer medium.

Direct Expansion (DX):

A geothermal heat pump system in which the refrigerant is circulated in pipes buried in the ground, rather than using a heat transfer fluid, such as water or antifreeze solution in a separate closed loop, and fluid to refrigerant heat exchanger. A DX system includes all of the equipment both inside and outside the house. DX systems may be single or multi-speed.

Integrated Demand Water Heating:

This term is used to describe geothermal heat pumps that include a water heating function in the refrigeration cycle. Integrated demand water heating differs from desuperheater in that the integrated demand water heating model provides all or nearly all of the domestic hot water needs and provides hot water even when space conditioning is not required. This includes systems that employ the use of a separate water heating compressor unit or that use the same compressor for space conditioning and water heating. Also sometimes referred to as full-demand or demand water heating.


Coefficient of Performance – A measure of efficiency in the heating mode that represents the ratio of total heating capacity to electrical energy input.


Energy Efficiency Ratio – A measure of efficiency in the cooling mode that represents the ratio of total cooling capacity to electrical energy input. For DX systems, EER will be calculated in accordance with the CSA standard C748-94 Performance of Direct Expansion (DX) Ground Source Heat Pumps conditions.

The above information came from the EPA’s Energy Star Web site:


The following came from the web site:

Copper Tube is Key to Success of DX GCH Systems

Direct-exchange geothermal systems use the earth as an energy reservoir, taking advantage of the constant 55°F temperature about 4 feet below the surface. Copper tubes run underground carry a refrigerant that circulates into and out of a home. A compressor unit induces heat exchange, and heated or cooled air is distributed through an air handler.

By running tubes underground, the heat-transfer medium in geothermal systems always enters a home at 55°F, unlike other systems that are exposed to much hotter and colder outside air temperatures. Once inside the home, the compressor concentrates and delivers the heat. To increase efficiency further in the air-conditioning season, waste heat can be transferred to the water heater. Research indicates that geothermal systems reduce heating and cooling cost an average of 30 to 60 percent when compared to air-source heat pumps.

According to studies conducted by utility companies, the greatest savings are provided by direct-exchange geothermal heating and cooling systems, since they burn no fuel and consume no energy beyond the electricity required to operate the compressor and the fan used to circulate the air.

Benefits of DX Systems vs Water-based Geothermal Systems

What sets direct-exchange systems apart from other geothermal systems is the fact that only one transfer is required for heat exchange, compared to the two steps required in water-based systems. In direct-exchange systems, the refrigerant is distributed through copper tube, which is in direct contact with the earth heat source for effective thermal transfer. Water-based systems rely on two transfer stages, requiring about twice as much energy, as well as a circulating pump, which is not necessary for direct-exchange systems.

The copper tube used in direct-exchange systems is an excellent heat conductor—much more efficient than the plastic tubes used in water-based systems. This conductivity enables copper systems to work more efficiently with smaller-diameter tubes than those used in plastic systems, so bore holes are smaller, reducing excavation and installation costs.

The following information came from the web site:

The EarthLinked® system provides:

  • Advantages over other types of systems;
  • Dealers/installers more options for easier low-cost installations;
  • Builders/developers an attractive technology upgrade that allows the builder to distinguish his product with high energy efficiency;
  • Architects/engineers technological advantages; decreased space requirements; a hidden system; an easier Building Energy Code compliance; and
  • Electric utilities more customers with electric space heating, water heating and total-electric homes; and peak-demand reduction in summer and winter.

A Uniquely Simple System

EarthLinked® is the simplest heat pump system available for heating and cooling any structure. ECR's refrigerant flow controls make it possible to directly access the solar energy stored below the earth's surface. No outside condenser/evaporator coil, fan blade or motor is needed. And no intermediate water loop with its associated circulating pump(s) and heat exchanger is required. The standard compressor is the only component necessary to circulate refrigerant through the ECR heat pump and the earth.

Engineered Solutions for Direct GeoExchange

Since 1980 ECR has been pioneering solutions to achieve successful direct geothermal exchange. Ten U.S. and nine international patents have been received. Its proprietary Refrigerant Flow Controls and DIRECT AXXESS® earth loops assure continuous oil circulation throughout the system, a higher system capacity and efficiency than those offered by other heat pumps, and an optimum refrigerant charge throughout the full operating range in both the heating and cooling cycles.

With optimal refrigerant flow control and engineered earth loop designs, mass flow of refrigerant is increased, earth loop size is decreased, as is the quantity of refrigerant used. Each EarthLinked® system is sized for the specific load and ground temperature where it is installed, so its efficiency excels in both northern and southern extremes.

Several other companies have offered direct geothermal exchange equipment. Early attempts were not successful, however, because of the various challenges faced by managing refrigerant in the earth loops. ECR's controls are highly engineered to provide the simplest, most reliable means of solving those challenges. In fact, the controls are so versatile that hundreds of sets have been used to improve the performance of systems sold by other manufacturers.


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