Geothermal

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Every GeoExchange heating and cooling system uses the earth as an energy source. A series of pipes called a loop works as a giant heat exchanger to connect the GeoExchange systems heat pump to the ground. Liquid circulating through the pipe acts as the transfer medium, collecting the earths heat in cold weather, and allowing heat from the home to be drawn off and returned to the earth during the air conditioning season.

The type of system used and the length and configuration of the pipe will depend on a variety of factors, including your area of the country, the configuration of your property, and the experience of your geothermal contractor.

HORIZONTAL CLOSED LOOP SYSTEM

This popular closed loop system is cost-effective for small installations, particularly for new construction where sufficient land area is available. Trenches are dug with a chain trencher or backhoe, and pipe is buried from three to six feet deep, usually in parallel rows, but configurations may vary to suit the landscape. The trenches are backfilled, taking care not to allow sharp rocks or debris to damage the pipes. A typical horizontal loop will require 400 to 600 feet of pipe per ton of heating and cooling capacity. When space is limited, overlapping coils can be used to fit the system into shorter trenches, although it requires more pipe. As with all closed loop systems, an environmentally safe antifreeze solution is circulated through the pipes. Horizontal systems are easiest to install when a home is being built, but new horizontal boring technology is making it easier to retrofit these systems into existing homes with minimal damage to lawns and landscaping.

VERTICAL CLOSED LOOP SYSTEM

This configuration is ideal when there isn't enough yard space for a horizontal loop, when the ground near the surface is too rocky or when larger heating and cooling capacities are needed. It's also ideal for retrofit applications because disruption to existing lawns and landscaping is minimal. Contractors use well-drilling equipment to bore vertical holes 150 to 450 feet deep. Each hole contains a single loop of pipe with a U-bend at the bottom. The holes are backfilled or grouted to protect the pipe and provide good thermal contact. The vertical pipes are then connected to a horizontal pipe which carries an antifreeze solution in a closed system to and from the GeoExchange heat pump located in the home. Vertical loops are generally more expensive to install and may be subject to local environmental regulations.

OPEN LOOP SYSTEM

An open loop system is a popular and very cost-effective construction option where a domestic water supply is needed and ground water is plentiful. Open loop systems have been used successfully for decades in areas where local codes permit. In this type of system, ground water from an aquifer is pumped directly from the well to the GeoExchange heat pump. After it passes through the heat exchanger, it is pumped back into a second discharge well located at least 50 ft. from the intake well. Excessive mineral content in the water may create problems in some equipment.