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.
B
Bookstar
19 Mar 2018 08:22
An air-source heat pump requires about 30% more electricity annually, based on both the information and the experience of my acquaintances. That means instead of 700 euros per year, it would be around 900-1000 euros. That's a maximum of 300 euros more per year.

The drilling for me would have cost 15,000 euros plus 20,000 euros for installation and piping. A simple payback calculation results in 66 years.

Forget it. That’s why there are very few ground-source heat pumps. I think the technology itself is great.
A
Alex85
19 Mar 2018 08:51
And for me, the drilling costs €6500. Of that, €5000 is covered by BAFA and about €1000 by subsidies in NRW. So now?
D
denz.
19 Mar 2018 09:01
Alex85 schrieb:
and about €1000 subsidy in NRW.

Quick question about this: That is a regional funding program. How did you find out about it? Is there a website where such funding programs are listed?
I want to build in Mecklenburg and haven’t found anything like that so far.

Regards
Denz
B
Bookstar
19 Mar 2018 09:55
Alex85 schrieb:
And for me, the drilling costs €6500. Of that, €5000 is covered by the federal funding program and about €1000 is a subsidy in NRW. So now?

Cool, soon they’ll even pay you to do it—things just keep getting better..
J
Joedreck
19 Mar 2018 10:54
Okay, listen up: Geothermal energy can also be installed using a trench collector laid directly yourself for around a maximum of 2000€ (approximately 2200 USD). And this is also supported by the BAfA. So basically, free money.

By the way: 15,000€ (about 16,500 USD) for the drilling is really extremely expensive.
S
Saruss
19 Mar 2018 11:26
Joedreck schrieb:
Now listen up: geothermal energy also works with a trench collector installed by yourself for a maximum of about 2000€ (around 2200 USD). And this is also subsidized by BAfA. So it’s basically free money.

By the way: 15000€ (around 16500 USD) for drilling is really expensive
However, a trench collector requires a suitable plot of land. Many trees and shrubs will not grow over it, and the soil often shifts significantly. It basically only works with a large lawn area. I also estimate that with renting an excavator and everything else, 2000€ (around 2200 USD) will be tight—you need materials and professional connections! Unless you happen to have contacts, but that is not the typical case.