The boreholes for heat pumps present closed system of heat exchange between solid rock and the heat pump itself – so-called system earth/water. This closed system is specific by hermetic collectors inserted to each borehole. These collectors, composed of two vertical connected polyethylene pipes, are filled with non-freezing mixture of spirit and water. When the compressor is running, this mixture is circulating in the collector, taking away solid rock so-called “dry” earth warmth (because it does not come in contact with the solid rock environment). The most important solid rock attribute is thus its conductivity and this is what the depth of each borehole is based on.

As the groundwater is not being used by this system at all, the depth of the borehole is not dependant on its inflow at all. Each borehole is after insertion of collector filled out with special cement-concrete mixture fulfilling two functions: it improves heat exchange between borehole walls and the collector and prevents cross-contamination of ground waters, because injected mixture presents waterproof plastic gel, once stiffed.

Air tightness of each borehole is verified with pressure test of the collector. Collectors are then brought out app. 1 meter above the terrain and secured for dirt. Shortly after ground works are done in depths 1.2–1.5 m where collectors’ ends are connected to the heat pump in the house. In the end, the collectors are covered by earth and are not visible at all.

For this house were made two boreholes, each 98 meters deep.

Vitocal 343:
Heat pump output: 6 kW
Integrated electric boiler output: 6 kW
Total output: 12 kW
Cooling output: 4,6 kW
Compressor electric input: 1,4 kW
Total electric input: 7,4 kW
Heat factor: 3.8
Sizes:
Height - 2085 mm
Width - 600 mm
Length - 677 mm
Weight (no water): 270 kg


Supplier of technology:

Viessmann
www.viessmann.com

Heat pump drills:
http://www.dpb.cz/heat_pumps/index.html

Floor heating distribution system:
Giacomini
http://www.giacomini.cz/arnema/ref4.html
http://www.giacomini.com