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The World of
Within the world of heat pumps, there are two (2) major technologies that operate in similar ways but pull from very different sources.
These two (2) options are:
1. Air-Source Heat Pumps (ASHP)
Exchanges heat with the outside air. This is not Geothermal Heating & Cooling.
2. Ground-Source Heat Pumps (GHSP)
Exchanges heat with the outside ground. This is Geothermal Heating & Cooling and include 'DX' and Water Based Systems.
ASHPs use ambient air outside a structure. They extract heat from the air, compress it and push it through indoor ductwork. In cold climates, the variable temperatures of the outside air makes this more challenging.
GSHPs, on the other hand, drill down just below earth's frost layer (4-5 feet) to use the more consistent heat energy underground.
Both systems use the same basic heat pump technology, but air-source heat pumps have to work much harder to extract the small amount of heat in ambient (outside) air when temperatures drop below freezing. During warmer seasons when air conditioning is required it's much harder to extract heat from the structure and vent it to the outside air.
Ground Source Heat Pumps pull from a much more stable source. Because of this, they are much more efficient at heating in the coldest winters, no matter what the outside air temperature - delivering more comfortable, efficient heating and cooling.
Air-Source Heat Pumps
Let's look more closely at air-source heat pumps. These units are being
used more as homeowners look for alternatives to heating their homes by
burning natural gas or other hydrocarbon-based fuels. They work best in
moderate climates as they provide a low heat supply and are most commonly
used with radiant heating to maximize the system in the cooler climates.
ASHPs come in a few different varieties and can be installed using exiting ductwork in a structure or in a ductless mini-split configuration. A mini-split system means you would have a central condenser installed as well as wall-mounted units in rooms you want to cool or heat. These mounted condensers have a significant effect on the home aesthetics.
Whatever the configuration is inside the home, air-source heat pumps start with a heat exchanger placed outside the house. The exchanger extracts heat or cold from outside air and moves it into the through an internal system. The outside component is subject to the elements and has a shorter lifespan.
Another important consideration is air-source systems are located above the ground, require a fair amount of space around the system to provide adequate air supply and have a visual impact on the property.
Ground-Source Heat Pumps
Ground-source heat pumps have been in use since the 1940s. These
systems use the earth itself as a heat source and sink by drilling down below
the surface, about 4 ft. in the northeast.
Below the frost layer, the earth maintains a nearly constant temperature
around 50-55 degrees Fahrenheit. This provides the foundation for a
predictable geothermal heating and cooling system. Think of it like a refrigerator.
There are two types of Ground Source Heat Pumps: 'Water Loops' use water/antifreeze as the heat transfer fluid; and 'Direct Exchange' (DX) using refrigerant as the heat transfer fluid. With both systems, piping, plastic in the case of Water Loops and copper in DX systems are buried in the ground near the structure. The fluid circulates inside the pipes and collects renewable energy from the ground. Each technology, Water Loops or DX, have an ideal application. Delivering a more healthful and comfortable indoor environment.
The ground-source system is located inside the structure providing longevity and eliminating any unsightly visual impact.
Ground-Source Heat Pump Distribution
Hydronics (hydro- meaning 'water') refers to one method a geothermal system uses to transfer heating and cooling throughout a structure.
Hydronics is the use of liquid water or a water solution (usually glycol with water - in water loop systems) as the heat-transfer medium and may include both a chilled and a heated water loop to provide for both heating and air conditioning. This method accommodates both radiant and forced air heating/cooling.
'DX' Direct Exchange geothermal is another method to distribute heating and cooling throughout structure. This is similar to conventional air conditioning; refrigerant is the heat/cool transfer medium distributed to air handlers. The application determines the heat transfer.
The Geo Group specializes in all ground-source heat pump and distribution systems.
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