Geothermal heat pumps heat and cool buildings by exploiting temperature differentials between the air above ground and the earth below it. They are clean and renewable and one of the most cost-efficient choices you can make when you decide to replace your old HVAC system.
But did you know there were different types of geothermal heat pumps?
Closed-Loop vs. Open-Loop Geothermal Heat Pump Systems
The basic distinction in heat pumps is between closed-loop and open-loop systems. Both systems include pipe buried beneath the ground, and both rely on heat exchangers to heat or cool the air in your home.
But closed-loop systems are entirely self-contained. They contain a mixture of water and antifreeze that circulates repeatedly through plastic tubing, transporting heat in one or the other direction.
Open-loop systems, on the other hand, circulate water extracted from underground or surface water sources, such as wells, rivers, ponds or lakes. Water is pumped in and drained out of the system continuously, using the original water source as both a heat source (in winter) and heat sink (in summer).
Closed-loop systems are more common, and they are divided into three subtypes: horizontal, vertical and pond/lake.
Overall, there are five varieties of geothermal heat pumps you’ll have to choose from, if you decide to install one. They are:
In horizontal closed-loop systems, pipes are buried in long trenches dug at least four feet deep underground. Common designs include one pipe buried at six feet and a second at four feet, or two pipes buried at five feet laid side-by-side.
Horizontal heat pump systems are appropriate for residential settings where a decent amount of surrounding acreage is available. Some horizontal systems make use of the Slinky ™ method of pipe looping, which decreases the quantity of land space required to install pipe horizontally.
In a vertical heat pump system, pipes are inserted into holes drilled about 20 feet apart and up to 400 feet deep. The pipes are connected by a U-shaped extension at the bottom and are further connected by shorter horizontal pipes laid horizontally in trenches.
Business owners and government agencies often choose vertical heat pump systems, since significant land space is often unavailable in the areas where they build. They are also a good option for homeowners in residential areas where the subsoil shallow or where lot sizes are small.
Properties with adjacent ponds or lakes have a unique option in geothermal heat pumps. Instead of running the pipes underground, they can save money on excavation by running them beneath the water. Temperature differentials between above-ground air and below-surface water are significant enough to make this approach viable.
To assure efficient operation in northern climates, pond/lake system tubing must be coiled at least eight feet beneath the surface of the water. If it’s run any shallower the system may freeze.
Fortunate accidents of geology give some people access to above-ground reservoirs or below-ground aquifers that are ideal for open-loop geothermal heat pump systems. Open-loop geothermal systems can be an attractive option for those who have access to appropriate water sources.
#5 Hybrid Systems
A hybrid heat pump will incorporate additional heating or cooling technology in the system. This will generally be a gas boiler or cooling tower, depending on what the addition was designed to accomplish.
Geothermal heat pumps work well in all conditions, since they harvest heat from underground where temperatures stay steady at 45-55 degrees all year round. Nevertheless, a hybrid geothermal system can make sense if expansion in heating or cooling capacity is needed. This is true when the cost of increasing the size of an existing geothermal system would be greater than the cost of adding a boiler or cooling tower.
Going Geothermal with ABE Heating and Cooling
If you’re thinking about purchasing and installing a geothermal heat pump, you’ll need expert advice before you proceed. At ABE we can answer all your questions about geothermal heat pumps and heat pump technology, and we’ll help you identify the best option for your home or business. We are located in Brighton, Colorado and serve the entire Denver Metro Area, and we are your best resource in the state if you need to learn more about heat pumps.