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What’s the Difference Between Open and Closed Loop Geothermal Systems?

What’s the Difference Between Open and Closed Loop Geothermal Systems?

geothermal systemsGeothermal heat pumps can save an amazing amount of money on heating and cooling bills. Both open and closed loop geothermal systems are capable of providing hot water, as well as heating and cooling the house. Before you go out and spend thousands of dollars though, it’s important to understand the difference between open and closed loop geothermal systems to pick the one that will work best in your situation.

Vertical Closed Loop

A vertical closed loop geothermal system requires the least amount of space. Loops of pipe containing refrigerant are placed vertically in the ground, requiring deep trenches but a small piece of land for installation. The depth and number of coils will depend on the overall capacity of the system, as well as how deep the onsite geological makeup will allow the equipment to go.

Vertical systems are a favorite for large schools and businesses. These systems can be created in virtually any size over a relatively small amount of land, though they may cost more than a horizontal system of similar capacity.

Horizontal Closed Loop

The average homeowner will usually opt for the horizontal closed loop geothermal system unless it’s on a tiny lot. This is the most common type of geothermal heat pump because of its convenience and relatively low cost, as well as the tendency of residential buildings to have yards or gardens attached. Top benefits of a horizontal system include:

  • Shallow trenches that are cheap to dig with a backhoe, as opposed to vertical systems that may require drilling several hundred feet
  • Easier to install and inspect, so they’re ready to use a lot faster
  • Only under a few feet of dirt for cost-effective repair or re-installation

A horizontal closed loop system that’s sufficient for most single-family residential buildings can fit under a decent-sized yard and is usually cheaper than other options. Installation is especially easy in newly constructed houses that don’t have established landscaping.

Water Source Closed Loop

The water temperature throughout Georgia stays just as constant as the ground, so it’s also a good choice for a geothermal source. With this system, the heat pump’s supply lines run straight from the house to the water, where the coils are placed deep enough to keep it at a constant temperature year-round.

One huge benefit to using a water source geothermal system is that there’s very little digging, which could translate into cost savings. It’s important to make sure that the water and the coils are sufficiently high quality to be safe over time.

Water source systems are also easier to repair or replace than any type of ground source system, though it’s even more critical to keep the coils in good condition to protect the surrounding ecosystem.

Open Loop System

Instead of sending refrigerant coils through an existing body of water, the open loop geothermal system circulates water from a well or similar ground water through the system. The water itself serves as the heat source in this system. Once it runs through the heat pump, water may be released into nearby surface bodies of water or pumped into a return well. Before installing an open loop geothermal system, it’s important to know local ordinances regarding safe water handling and lawful disposal.

Open loop systems are easy to install if you have existing wells, though their capacity is restricted by the volume of water that’s available. This type of system doesn’t need a lot of surface space, so it could be a great option if you don’t have the space for horizontal coils but don’t have needs high enough to justify the expense of a vertical system.  Because it uses water instead of refrigerant, this system will go through a substantial volume every day during the heating or cooling season.

Both open and closed loop geothermal systems can provide efficient, reliable heating and cooling throughout your home. Local regulations regarding ground water may affect your choice, as will the size and geological makeup of your property. All geothermal systems involve a fairly substantial initial investment, but there may be renewable energy incentives available that can help offset some of the installation costs.

To get more information on open and closed loop geothermal systems, or to have a new system installed, contact us at McDevitt Air. We’re the go-to source for your HVAC needs in the Bluffton, Savannah and Pooler areas.

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