By Kevin Burns

Green HVAC technologies are on the rise, and the market for them will only continue to expand over the next few years. The HVAC industry has been an early adopter of new technologies since the first days of residential and commercial air conditioning in the early 20th century and when it comes to integrating green technologies, specifically the renewable resource of geothermal energy, it is once again ahead of the game.

What is Geothermal Technology — And Why Does it Matter?

The word “geothermal” refers to the heat generated by the earth. Geothermal technology can hardly be called new — historians say American Paleo-Indians were harnessing geothermal energy in the form of hot springs for cooking, bathing, cleaning, and other tasks as far back as 10,000 years ago! Modern usage began in the early 20th century, when an Italian scientist harnessed geothermal energy for an electric power plant.

Geothermal HVAC systems are on a much smaller scale than geothermal power plants and though they operate on the same principle of converting the earth’s heat into energy, HVAC systems can also harness the earth’s cool as well (more on that later).

The first HVAC system using a geothermal heat pump was introduced to the US in 1948, but it wasn’t until the 1970s oil crisis that the relationship between geothermal and HVAC technologies really warmed up, as all industries sought cheaper energy alternatives to oil, including solar, wind, and of course, geothermal sources. Over time, it became clear that these technologies were also an environmentally friendly solution to heating and cooling, and this was a growing priority for the HVAC industry.

The HVAC industry’s role in environmental sustainability developed at a rapid pace in the 1990s, beginning in 1994 with the realization that freon, one of the chemicals involved in the cooling process, was linked to ozone depletion. This led to an onset of research by government and industry into environmentally friendly alternatives, energy efficiency, and other innovative measures to ensure HVAC systems performed as well as they could with as little environmental impact as possible.

How Geothermal HVAC Systems Work

You already know that the practice of using geothermal energy has been around for thousands of years and that it’s been used formally by industry since the early 20th century. But how does this actually apply to the HVAC industry today?

In a nutshell, geothermal technologies harness the energy generated and naturally regulated temperatures just a few feet below the surface of the earth to control indoor temperatures. The temperature around six feet down doesn’t fluctuate nearly as much as surface temperature, which means that in hot weather it’s cooler than the surface and in cold weather, it’s warmer than the surface.

Geothermal systems are typically twice as efficient as the best air conditioners and 50% more efficient than gas furnaces. They’re environmentally friendly because they use existing energy while releasing no emissions.

Geothermal units are comprised of 3 things: 1) buried pipes filled with refrigerant liquid, called loops, 2) a pump that leads into a building to circulate the liquid that is either heated or cooled by the ground beneath the building, and 3) an above-ground management system. In the warm, summer months, the loop draws heat out of the house and in the winter, it pushes heat into the house. There are a few specific types of these systems: closed-loop, open-loop, and hybrid.

Closed-loop systems are just what they sound like and involve the refrigerant being moved through a closed loop system. There are three main types of closed-loop systems:

• horizontal systems: the best option for residential new-builds, since they lie stretched out beneath the footprint of the house
• vertical systems: the typical choice for industrial applications because they require a significant amount of land and involve digging up to 400 feet deep
• pond or lake systems: these involve placing the loop in a body of water, where it won’t freeze

While closed-loop systems require refrigerant, open-loop systems use water from a nearby body of water. Finally, hybrid systems combine geothermal systems with other systems, including conventional air systems, and work best for buildings that require more cooling than heating.

When it comes to the environmental benefits of the different systems, closed-loop systems require refrigerant, which is slightly less eco-friendly than the water-circulating open-loop systems, but they’re still a much greener alternative to traditional HVAC systems and have fewer emissions. And while all of the systems require electricity to operate, they still rank above wind or solar power in terms of reducing energy consumption on the electrical grid. Finally, geothermal HVAC systems last for years — if not decades — longer than traditional systems, which only adds to their appeal.

Impact of Geothermal Technologies

Geothermal technologies have the potential to play a huge role in the HVAC industry, especially with the growth in the green tech market. They appeal to consumers and industry alike for countless reasons, including their green nature and the fact that they’re cheaper (and quieter!) to operate than traditional systems.

The industry appeal of geothermal technology is heightened by the fact that the government actually incentivizes the development of geothermal HVAC technology, as well as its installation and maintenance. In today’s carbon-aware climate, it increasingly pays to be environmentally friendly.

As the popularity of geothermal technologies increases, so does the associated level of research, innovation, and investment. You can look forward to even more developments when it comes to increased efficiency, reduced environmental impact, and cost savings over the next couple years. In recent years, people have even been learning to harness these technologies for things like snow melting, pool heating, and other innovative methods around the home and in commercial buildings.

It’s exciting to know that in the coming years, the number of ways geothermal technologies and the HVAC industry will work together should only continue to grow.

About the Author

Kevin Burns is the President of Bob Jenson Air Conditioning in San Diego with over 29 years of experience in the HVAC Field. He has worked in every aspect of the industry and has trained dozens of people. He has a passion for doing what’s right for each home and customer and sets this standard for his entire team.