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GEOTHERMAL DIRECT EXCHANGE

The following came from the web site:

http://www.copper.org/applications/plumbing/heatpump/geothermal/gthrml_main.htm

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:

http://www.ecrtech.com/content/interior.asp?section=products&body=advantages.htm

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.