Geothermal Heating and Cooling: Closed Loop Vs. Open Loop Systems

There’s a lot to like about geothermal heating and cooling. That’s probably why it’s now the fastest-growing renewable energy source for home heating and cooling in the United States. Homeowners are impressed by geothermal’s superior efficiency—in heating mode, a geothermal system is 70 percent more efficient than other heating methods—and low environmental impact.

The simplicity and long life of geothermal components is another big plus.

Geothermal extracts latent heat from the ground near your home or from a nearby source of water, like a well or pond. Because temperatures underground and in deep water remain a consistent level year-round, this heat can be concentrated by a heat pump then dispersed through your home for warmth in winter. In summer, the process reverses as interior heat is removed and dispersed back to the earth or water well.

Two types of geothermal systems predominate in residential applications

• Closed-loop: In a ground-sourced closed-loop system, horizontal or vertical loops of plastic tubing buried underground on your property continuously circulate heat-exchanging fluid. This fluid absorbs latent heat from the ground and conveys it to an indoor heat pump and compressor. The heat is concentrated, then dispersed by an indoor coil into your home. Cooled fluid then circulates back to the loop field to absorb more heat. For cooling in summer, the earth acts as an effective heat sink to absorb heat extracted from the home.

• Open-loop: The open-loop system is utilized in water-sourced geothermal installations. Water from a well or deep pond is pumped directly to the water-source heat pump where latent heat is extracted from the water then transferred to the refrigerant, concentrated by the heat pump and dispersed into the home. The cooled water is then returned to its source through a separate discharge well or pumped directly back to the pond. Open-loop systems require a very dependable, unvarying source of deep water.

Sobieski Services offers the cutting edge of sustainable energy like geothermal heating and cooling.

Our goal is to help educate our customers in Delaware, Pennsylvania, Maryland and New Jersey about energy and home comfort issues (specific to HVAC & plumbing systems).

Image Credit: TangYauHoong