Ground Source Heat Pumps
These heat pumps are fundamentally the same as the air-source heat pumps, when it comes to the way the systems work on the inside of the house. The main difference is that these units are extracting and dumping heat into the earth, instead of into the outside air. This makes them much more efficient, as the earth's temperature is fairly constant. This also means that these system can produce more heat in the winter than their air-source relatives. Since our region is heating dominated, this means a great deal!
Designing the Ground-Source Heat Pump System
The most important part of a ground-source design is the loop-field. Since most systems in our area will be vertical (drilling bore holes) systems, minimizing the amount of drilling can save quite a sum of money.
There are a few things that affect the required length of the boreholes:
- The heating load of the house (more efficient house = less drilling)
- The thermal conductivity of the grout (fills the air space between the pipe and the ground)
- Capacity of the selected equipment (oversizing = more drilling)
