Average

Range

Typical Value*

Number of Boreholes for Vertical GHP

207**

18 - 928**

Varies

Borehole Depth [m]

Vertical: 63

Horizontally bored: 10

Vertical: 46 - 91

Horizontally bored: 7.6 - 12.2

Vertical: 15 - 137 Horizontally bored: 9.1 - 15.2

Borehole Separation Distance [m]

4.9

2.4 - 6.1

4.6 - 6.1

Borehole Length per kW [m/kW]

18.0

7.2 - 31.3

13.0 - 21.7

GHP water flow rate per kW [L/min/kW]

3.7

2.3 - 5.8

2.7 - 3.2

Heat Pump Efficiency Range

Cooling: 4.16 - 5.07 COP Heating: 3.1 - 3.9 COP

Cooling: 2.46 - 8.79 COP Heating: 2.5 - 6.4 COP

Mini. Cooling: 3.93 COP*** Mini. Heating: 3.1 COP***