Components

Ground loop

In geothermal systems, the ground loop acts as the heating or cooling agent. It may be in the ground or in groundwater, making a closed loop. It can also be connected to a conventional well, making an open loop.

In a closed-loop system, a mixture of antifreeze and water circulates through the ground loop and heat pump. In winter, the fluid draws heat from the ground or groundwater, and in summer, it draws heat from your home and discharges it underground. Closed loops can be horizontal or vertical, and can also be submerged in groundwater. Vertical closed loops are the most common because of their suitability for average-sized lots.

In open-loop systems, groundwater from an ordinary well is the heat source. The pump draws water from the well, and the heat pump extracts heat from it by means of a heat exchanger. The water is then discharged into the earth, usually through a return well.

Heat pump

The heat pump transfers heat between the ground loop and the house.

In winter, it concentrates heat from the ground loop and transfers it to the house. In summer, it transfers heat from the house to the ground loop, which discharges it into the ground.

You should consider how much room you have in your house for a heat pump.

Distribution system

Like all central heating and air-conditioning systems, geothermal systems must be combined with a distribution system – forced-air or hot-water – to distribute heating and cooling throughout the house. In existing homes, ducts or radiators may require modification.