What Is Geothermal Heating?

What Is Geothermal heating and how does it work? We’re here to answer these questions and more in Design Flow HVAC’s guide to Geothermal heating.

A typical home in the U.S. consumes nearly half its energy for heating and cooling. For office buildings, the ratio is even higher. While there are all sorts of suggestions to reduce AC usage or adjust thermostats, the most energy efficient solution is a geothermal heat pump. This technology makes use of the solar energy that always resides underground, rather than generating heat as a traditional HVAC system does. It’s also quiet and eco-friendly.

The Geothermal Heating Process

Geothermal heating is a resource that’s available worldwide. You don’t need to live near a volcano or hot spring to take advantage of latent heat energy from the Earth. Below ground, the temperature is typically constant year-round. On average, the temperature increases about 1 for every 70 feet of depth, but adequate temperatures for a geothermal system are usually just a few feet down.

About half the sun’s energy is absorbed into the ground. Geothermal energy is not only supplied by the sun; radioactive decay of minerals also contributes to this underground renewable energy source. This energy can be tapped by burying pipes below the surface. This doesn’t require extra square footage because the pipes can be placed below your yard or driveway.

The pipes carry a liquid to and from a geothermal heat pump in your basement, which removes heat from the liquid and transfers it to your ductwork. Geothermal technology is therefore compatible with forced-air heating systems while avoiding the burning of fossil fuels. It also requires much less electricity to run.

A geothermal heat pump can work in heating or cooling mode. Here’s how both processes work:

• Heating Mode: The heat pump in your home pushes a fluid into buried pipes or ground loops, which then absorbs heat from the warmer underground substrate (soil, rock, water, etc.). Heated fluid is circulated back to the building, while a heat exchanger transfers the heat into the existing air handling, distribution, and ventilation system. Your domestic water supply can even be heated, through the use of a desuperheater. The same fluid, now at a lower temperature, is delivered back to the ground loop to be reheated.
• Cooling Mode: By way of a heat exchanger, fluid absorbs heat from indoor air. This heated air is pumped through underground lines and heat is discharged into the soil, rock, water, or other underground material. As the fluid circulates, its temperature decreases; lower temperature fluid is then pumped back to the building, where it absorbs heat all over again. The process repeats to provide continuous cooling. Since these processes can be reversed, a geothermal heat pump can be used during the summer or winter.

Types of Geothermal Heating Systems

Geothermal systems can be configured in a variety of ways. This gives you a few options if you’re considering an investment in geothermal heating. The choices you have include:

• Closed Loop: A continuous series of underground pipes are filled with a liquid solution that transfers energy to and from the heat pump. These pipes can be configured vertically by drilling a well, or horizontally directly under your yard.
• Open Loop: Groundwater is used as a direct heat source. It is pumped directly to the heat pump, so geothermal energy is therefore transferred without using a closed pipe system or specialized liquid solution.
• Pond/Lake Hybrid: A pond or lake is connected in an open loop with the heat pump. Geothermal energy is obtained and transferred from the heat content of this nearby water source.

Direct use geothermal systems tap groundwater as hot as 200℉ in areas of high volcanic or tectonic activity. These systems can provide large-scale heating for buildings, pools, roads/sidewalks, and industrial or agricultural processes. Deep geothermal systems, on the other hand, use steam from a mile or more underground, which can be hundreds of degrees Fahrenheit. They can support clean heating and electricity generation in a range of applications.

Contact Design Flow HVAC

Geothermal technology provides access to an unlimited source of heating or cooling, and is 200 times more efficient than using air to transmit heat.² We offer a range of geothermal services as well as geothermal heat pump installation in and around Eldersburg, MD. Our technicians are trained and experienced at installing and repairing different types of geothermal systems. To get started, call us at 301-708-2692 today!