Savings – Calculated $2,800 CAD/year energy cost, displacing 4,100 litres/year of heating oil, 12 1/2 Ton/year CO2 equivalent reduction
Type – Forced air, closed loop, water to air, desuperheater
Groundloop – Horizontal slinky, 600′ of trench, 5,000′ of pipe
Heat Pump Capacity – 53.7 kBTU heating, 70 kBTU cooling
Slinky ground loops are somewhat unpopular due to their ability to extract energy at a rate higher than that which can be replenished by most soil, if designed incorrectly. This concentrated heat exchanger can work to your advantage by reducing the footprint when compared to 2 or 4 pipe per trench horizontal, and significantly reducing installation cost over vertical and traditional horizontal ground loops.
Another advantage of this type of groundloop is the quick installation due to the fact that the loops can be assembled and pressure tested ahead of time and simply “folded” into the trench, of particular interest in saturated soils that cave easily, such as with this project.
Loop thermal expansion tank, air distribution and return as well as auxiliary plenum heat are all important parts of this installation.
Careful design and arrangement of circulating pumps is responsible for moving the heat transfer fluid from the heat pump to the field and back. Transferring just the right amount of heat at a specified flowrate to or from the heatpump, depending on the mode – heating or cooling.
Despite the obvious…impact a horizontal ground loop can have on a site, its important to remember that the grass grows back. The photo below was taken of the field 2 months after the ground loop above was installed.