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 How GHP Systems Work
GeoExchange systems, like common heat pumps and air conditioners, make use of a refrigerant to help transfer (or pump) heat into and out of your home. The refrigerant helps the GeoExchange system take advantage of two primary principles of heat transfer:
- Heat energy always flows from areas of higher temperature to areas of lower temperature.
- The greater the difference in temperature between two adjacent areas, the higher the rate of heat transfer between them.
Refrigerators, air conditioners, and heat pumps all operate by pumping refrigerant through a closed loop in a way that creates two distinct temperature zones--a cold zone and a hot zone.
The simplest example of such a system is the universally familiar home refrigerator. In a refrigerator, a fan blows the air inside the box over tubes containing refrigerant that is very cold (typically below 0° F). Heat flows from the interior air to the cooler refrigerant. The refrigerant is then pumped to the high-temperature section, which is exposed to room air outside the refrigerator box. Because the refrigerant is hot in this zone, it gives up heat to the relatively cooler air in the room, before flowing back to the cold zone to begin the loop again.
An air conditioner works in exactly the same way, except that it extracts heat from the air inside a room or building and transfers it to the air outside the building.
A conventional heat pump adds a reversing capability, so the hot zone and the cold zone can be switched. With the zones reversed, it can extract heat from the outside air in the winter and transfer it inside.
Granted, being able to extract heat from frigid winter air seems like it shouldn't work, but it will if we can expose the cold air to refrigerant that's even colder than it is. And modern heat pumps can do that.
When the outside air gets extremely cold, the conventional (air source) heat pump has to resort to electric resistance heating. This reduces efficiency dramatically.
GHP System In The Summer
GHP System In The Winter
Benefits
- Greatly reduced energy costs
- Reduced emissions of greenhouse gases and other pollutants
- Higher installation cost is paid for in just three to five years of energy savings
- Quiet operation
- Low maintenance costs
- Suitable for warm or cold climates
Cool Facts
- Used in homes, stores, office buildings, and public buildings nationwide including 450+ schools in 30 states
- Able to heat and cool a typical 1,500sf home in a moderate climate year-round for $1 a day
- Can handle a home’s hot water needs given the right climate and environment
- A typical homeowner will pay $30 extra per month on the mortgage for a GHP system but will save $40 or more on energy and maintenance costs
- Environmentally friendly -- no venting or pollution here!
- The cost of a GHP will typically pay you back in less than 40 months
Portions © Geothermal Heat Pump Consortium
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