Geothermal HVAC aka "Heatpumps"
The farm construction project has lots of details. Most of them represent unfamiliar territory to me.
From the very start, I intended to employ a heatpump system. I knew a little about them from years ago but knew they were difficulty to complete in the Northeastern USA. They work well for air conditioning but getting heat was is more challenging.
I’m still planning to use a heatpump but now I know there are many different types and to be more specific, I plan to use a geothermal ground water closed vertical loop heat. The system starts with a series of wells being drilled. Two tubes, connected with a 180 connector at the end (creating a very tall “U”) are lowered into each well. The number of wells is determined by the are to be heated and cooled. All of the well leads are connected in series. The closed loop is connected to the heat exchanged. Here is a video that shows the wells and the tube segments as well as the overall system.
There are lots of ways to explain how a geoexchange system. I find it easiest to refer to a refrigerator. Inside it is cold and it generates excess heat, exhausted out the bottom and back. In the summer, consider the house as the inside of the refrigerator and the excess heat is exhausted into the ground. In winter, the system is reversed and the “excess heat” is exhausted into the house. It’s an over simplification. For a more detailed and accurate explanation, read “how it works“.
It’s also possible to get part or all of a building’s hot water from the system. One solution uses the compressor’s excess heat generated as a by-product of operation. This heat can be captured for the hot water system. A conventional hot water system is still needed for times when the geothermal is not operating (spring and fall). In some cases a separate mini-heatechanger is used to provide 100% of the hot water needs - triple function geoexchange systems.
All photos courtesy of Geothermal Heat Pump Consortium, Inc.
