ᐅ Experiences with Ground Source Heat Pumps

Created on: 23 Oct 2015 21:40
S
Saruss
Hello,
here I would like to share some experiences and data regarding my brine heat pump and deep drilling, based in part on the expert’s "questionnaire":

a) What is the soil composition on your property?
Up to 3m (10 feet) silty, fine sandy, clayey soil
Up to 4m (13 feet) slope debris, rock fragments
Then bedrock (mainly limestone)

b) How deep was the drilling?
Drilled twice to a depth of 72m (236 feet)

c) How much did the drilling cost?
€10,400 including double U-probes DN25
Grouting material with 2.0 W/mK thermal conductivity
Permitting process (building permit / planning permission)
Pressure-tight house entry at the basement and underground routing of supply lines (about 25m (82 feet))
Filling/draining equipment, filling, pressure testing, etc. (all inclusive)

d) How much did the system cost?
System: Tecalor TTc 05 with heating output at B0/W35 of 5.8 kW and coefficient of performance (COP) of 4.8
Cost: €9,800

e) Were there any difficulties during installation, if so, what kind?
Because the water used to flush out the drilled material during drilling seeped away, a "small compressor" was needed to blow it out with air. However, it had to be placed on a neighbor’s property who had not yet started building. The machine was the size and approximate weight of a 20-ton truck but was off-road capable. This caused a 2-day delay because the compressor first had to be transported to our site. No additional costs were charged.

f) How is the daily operation?
"Like a refrigerator." Once the parameters on the heating system are correctly set, the only thing that should be done is occasionally reading the information/data such as operating hours and source temperature. Otherwise, it runs "on its own," just like any heating system. When the door is closed, the unit is virtually inaudible. Very discreet since, apart from the cabinet in the utility room, nothing else is visible (all brine pipes are underground).

e) What are the operating costs for which living area?
Currently, a living area of 180sqm (1937 sqft) is heated, plus an additional 65sqm (700 sqft) of cellar space within the insulated thermal envelope (these rooms are around 15-16°C (59-61°F) on the coldest days). From September 2014 to September 2015, 2,000 kWh of electricity was consumed for heating and hot water (2 adults, 1 baby, 1 toddler). The house is a KfW-70 standard building according to the 2009 energy saving regulations, which already met the required technical standards before the central ventilation system with enthalpy heat exchanger was installed (we decided to add this after the initial applications).

f) to be continued ....

Note regarding the comparison of the coefficient of performance (COP):
Since optimizing the heating curve and settings at the end of last year, the system has had a COP of about 5.5. Operating hours are around 1200; the deep borehole was drilled approximately 20% deeper than initially recommended by the companies, at our own request.
ares8322 Mar 2018 18:22
It doesn’t get any more accurate. Off the top of my head, I can name at least four users here in the forum who would qualify for this funding, including myself. We have actually already received the money. By the way, you don’t really have to meet the values exactly in practice.
T
toxicmolotof
22 Mar 2018 18:39
ares83 schrieb:
It doesn’t get any more accurate than this. Off the top of my head, I can name at least four users here in the forum who would qualify for this subsidy, including myself. We have already received the funds. By the way, you don’t actually have to achieve the values in reality.
I wouldn’t be so sure about that. Does the funding agency reserve the right to conduct on-site inspections?

Are heat meters required to be installed?
ares8322 Mar 2018 18:58
toxicmolotow schrieb:
I wouldn’t be so sure about that. Does the funding provider reserve the right to inspect on-site?

Do thermal energy meters have to be installed?

Of course, the installed ones are sufficient. According to BAFA’s FAQ: If the heat pump does not meet the annual performance factor, that’s not a problem. Differences between theoretical and actual performance do not lead to a repayment of the subsidy.

Which is also reasonable, since the first year is not very indicative due to construction moisture, start-up program, etc.
R
R.Hotzenplotz
25 Mar 2018 19:44
Is the geothermal borehole for the brine heat pump drilled directly at the location where the heating system will later be installed? In other words, once the basement is built, is it already too late for this? They won’t be able to bring such equipment into the utility room anymore.
S
Saruss
25 Mar 2018 19:49
R.Hotzenplotz schrieb:
Is the drilling for the ground probes of the brine heat pump done directly at the spot where the heating system will later be installed? Does that mean it would be too late once the basement is built? They wouldn’t be able to bring such equipment into the utility room anymore.
The drilling is usually done outside the building.
A
Alex85
25 Mar 2018 19:52
Yes, drilling underneath the slab is uncommon but definitely possible. However, this must be done before the slab is poured. Otherwise, drilling is done several meters away from the house and introduced into the building using core drilling.

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