Diagram of a brine/water heat pump system with ground collectors

Key information:

  • Geothermal energy recovered by a ground collector or vertical/borehole heat exchanger.
  • Temperature at a depth of over 1.2 meters does not fall below 0°C.
  • Installation of heat pump in a dry room with temperature above 0°C.
  • Option of heating and heating of sanitary water.
  • Availability of energy source throughout the year.
  • Monovalent operation mode.
  • Simple electronic control of the system.
  • Basic configuration allows 1 mixing and 1 direct heating circuit.
  • Using the expansion modules, up to 32 mixing circuits can be controlled.
  • Allows two independent hydraulic circuits.
  • Passive cooling option.



Brine/water heat pumps use the heat stored in the ground as the source of energy. A huge amount of energy is stored in the ground, generated by precipitation and sunlight. Two systems are available for continuous recovery of heat from the ground: ground heat collectors, and borehole heat exchangers.

TERRAGOR heat pumps are highly economical and they reach COP values over 4.5. The difference between input temperature of the medium (water + glycol) and output temperature at the collector is approximately 4°C. In the brine/water heat pump system, minor adjustments can also be made to allow passive cooling



Horizontal ground collector

Brine/water heat pumps make use of  the energy accumulated in the soil. The  energy is recovered from the soil using  a ground heat collector laid over an adequately sized surface. For optimum operation, the collector surface must be approximately twice the size of the heated area. The amount of energy retrievable from the soil depends on soil composition and position. It is important that the surface on which the ground collector is laid is not built on or asphalted; in other words that nothing obstructs the passage of precipitation through the surface.

The required size of the collector can be roughly calculated as follows: heating pump heating power (in kW) × 40. Required cross-section of PE pipe is 1” and they must be laid approximately 120 cm below ground surface level, with a gap of 0.7 to 0.8 meters between the pipes.


Vertical heat exchanger

If the surface available to build a horizontal ground collector is not sufficient, a vertical/borehole heat exchanger can be drilled to make use of the geothermal energy. Approximate required depth of the borehole can be calculated as follows: heat pump heating power (kW) × 14 = borehole depth (m).

Passive cooling

In the TERRAGOR heat pump system, minor adjustments can also be made to allow passive cooling. In this case, relatively low ground temperature is used to cool the
rooms. During passive cooling, the heat pump is not in operation, which allows minimum energy consumption for cooling and thus, compared to conventional air conditioning, much
lower electricity bill.

Technical characteristics of heat pumps TERRAGOR

Model HP BW 6 HP BW 9 HP BW 11 HP BW 14 HP BW 17
Dimensions (VxŠxG) mm 815x654x580 815x654x580 815x654x580 815x654x580 815x654x580
Mass kg 82 91 113 124 128
Heating water temeprature °C 55 55 55 55 55
Refrigerant / R407C R407C R407C R407C R407C
Refrigerant - mass kg 2 2,1 2,3 2,5 2,7
Sound level power* dB(A) 52 (±1,5 dB) 52 (±1,5 dB) 52 (±1,5 dB) 52 (±1,5 dB) 52 (±1,5 dB)
Water flow - heat source m3/h 1,70 2,20 2,80 3,52 4,13
Water flow - heating m3/h 1,20 1,60 2,0 2,45 2,95
Power supply/ Fuse V/A 400/C10 400/C10 400/C16 400/C16 400/C16
* Measured according to standard DIN EN 3750.

Technical characteristics at different heating water temperatures

Heating power/ Rated power (B0/W35)** kW 6,5/1,51 9,2/2,04 11,7/2,60 14,4/3,20 17,0/3,70
COP (B0/W35)**   4,3 4,5 4,5 4,5 4,6
Heating power/ Rated power (B0/W45)** kW 6,3/1,97 8,8/2,59 11,1/3,17 13,8/3,94 16,1/4,47
COP (B0/W45)**   3,2 3,4 3,5 3,5 3,6
Heating power/ Rated power (B0/W55)** kW 6,0/2,40 8,5/3,27 10,5/4,19 13,3/5,11 15,3/5,88
COP (B0/W55)**   2,5 2,6 2,5 2,6 2,6

** Measured at parameters brine-water B0/W35-55; according to standard EN 14511.

HP BW 14 - Comparison of electric and heating power at different source temperatures

17 kW | heating water up to 35°C

Source temperature °C -5 0 5 25
Rated power kW 3,7 3,7 3,9 4,3
Heating power kW 14,4 16,7 19,2 29,1
COP / 3,9 4,5 5,0 6,8

17 kW | heating water up to 55°C

Source temperature °C -5 0 5 25
Rated power kW 4,9 5,1 5,3 5,9
Heating power kW 13,0 15,1 17,5 26,4
COP / 2,7 3,0 3,3 4,7