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.
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.
Bookstar schrieb:
There is often a lot of discussion in forums with little evidence, unfortunately. I just checked again—when I compared providers a few years ago, the geothermal drilling plus connections cost 18,000 euros. The air-source heat pump was 13,000 euros less expensive after subsidies. So, the payback period for geothermal was about 30 years. We decided against it and have no regrets so far.
At that time, I requested quotes from four companies, and their prices were quite similar. Therefore, I think either it has become much cheaper since then (which is doubtful), people only share partial information (very likely), or it varies a lot by region (possible).[USER=20319]@Bookstar or some people are close-minded and do not accept differing opinions, findings, or facts. I, and I think others above as well, provide absolutely accurate figures. You have provided less evidence than we have and generalized much more (and your numbers above: comparing an air-to-air heat pump with subsidies to a ground-source heat pump without subsidies is not entirely fair either). I have disclosed all figures related to the entire construction project here. Will you only believe it if I send you the invoices?M
Mastermind119 Mar 2018 21:34We built our house in 2009.
It was between the KfW 60 and 40 energy efficiency standards of that time.
Heating demand was about 12,000 kWh.
Electricity prices back then were around 15 cents/kWh.
An offer for geothermal drilling was around €13,000, with the drilling depth based on an estimated heating load.
The first proposed air-source heat pump was supposed to have a heating capacity of 12 kW.
That seemed way too high to me.
So we had a heating load calculation done by an engineering firm.
Design temperature was -14°C (7°F).
Heating load without the basement was just under 6.5 kW.
With heating in our party/hobby basement room, it was just under 8 kW.
Due to the supposedly high drilling costs (which were based on the 12 kW heating capacity), we opted for a smaller Stiebel air-source heat pump.
Unfortunately, this air-source heat pump and its hydraulic setup were poorly installed.
Electricity consumption: 4,000–4,500 kWh (seasonal performance factor 2.8).
A brine heat pump would have easily achieved a seasonal performance factor of 4 to 4.5, even with a “poor” installation.
Drilling costs for 6 kW would have been about €10,000. The geothermal heat pump itself would have cost nearly €2,000 less.
The real extra cost for geothermal would have been closer to €8,000.
Electricity demand with a geothermal heat pump and a seasonal performance factor of 4.5:
12,000 kWh ÷ 4.5 = 2,666 kWh. Compared to our air-source heat pump’s consumption of 4,000 to 4,500 kWh.
That means additional electricity costs today amount to around €330 annually.
The electricity price that served as the basis for our decision to go with the air-source heat pump has since risen by nearly 80% from 14–15 cents to about 25 cents.
At the end of the day, we are self-critical and would not choose an air-source heat pump again based on our negative experiences.
Heating system installers are often not interested in setting up an efficient heat pump system.
Hydraulics, design of underfloor heating, hydraulic balancing, no buffer tank, no individual room controllers... these are all aspects that many installers just set up “as usual.”
And this is also our problem with our air-source heat pump.
A brine heat pump is more “forgiving” due to the constant ground source temperature compared to an air-source heat pump with very low outside air temperatures in winter.
The air-source heat pumps typically offered by standard heating installers are usually only “standard” in terms of efficiency.
The best models still come from East Asia (Panasonic, Mitsubishi, Daikin)—but a normal heating installer usually won’t install Daikin.
Given the currently very good government incentives from BAFA, I would definitely choose geothermal today.
It was between the KfW 60 and 40 energy efficiency standards of that time.
Heating demand was about 12,000 kWh.
Electricity prices back then were around 15 cents/kWh.
An offer for geothermal drilling was around €13,000, with the drilling depth based on an estimated heating load.
The first proposed air-source heat pump was supposed to have a heating capacity of 12 kW.
That seemed way too high to me.
So we had a heating load calculation done by an engineering firm.
Design temperature was -14°C (7°F).
Heating load without the basement was just under 6.5 kW.
With heating in our party/hobby basement room, it was just under 8 kW.
Due to the supposedly high drilling costs (which were based on the 12 kW heating capacity), we opted for a smaller Stiebel air-source heat pump.
Unfortunately, this air-source heat pump and its hydraulic setup were poorly installed.
Electricity consumption: 4,000–4,500 kWh (seasonal performance factor 2.8).
A brine heat pump would have easily achieved a seasonal performance factor of 4 to 4.5, even with a “poor” installation.
Drilling costs for 6 kW would have been about €10,000. The geothermal heat pump itself would have cost nearly €2,000 less.
The real extra cost for geothermal would have been closer to €8,000.
Electricity demand with a geothermal heat pump and a seasonal performance factor of 4.5:
12,000 kWh ÷ 4.5 = 2,666 kWh. Compared to our air-source heat pump’s consumption of 4,000 to 4,500 kWh.
That means additional electricity costs today amount to around €330 annually.
The electricity price that served as the basis for our decision to go with the air-source heat pump has since risen by nearly 80% from 14–15 cents to about 25 cents.
At the end of the day, we are self-critical and would not choose an air-source heat pump again based on our negative experiences.
Heating system installers are often not interested in setting up an efficient heat pump system.
Hydraulics, design of underfloor heating, hydraulic balancing, no buffer tank, no individual room controllers... these are all aspects that many installers just set up “as usual.”
And this is also our problem with our air-source heat pump.
A brine heat pump is more “forgiving” due to the constant ground source temperature compared to an air-source heat pump with very low outside air temperatures in winter.
The air-source heat pumps typically offered by standard heating installers are usually only “standard” in terms of efficiency.
The best models still come from East Asia (Panasonic, Mitsubishi, Daikin)—but a normal heating installer usually won’t install Daikin.
Given the currently very good government incentives from BAFA, I would definitely choose geothermal today.
T
toxicmolotof19 Mar 2018 21:55Where do you all live, or where do you have to drill through obsidian? Our 100 meters (330 feet) of drilling cost around 5,000 euros.
An annual performance factor of 2.8 is really poor for a modern air source heat pump system. We are achieving 3.5, and as you mentioned, a ground source system would probably have 4.5 or more, I think.
The drilling you mentioned is certainly interesting – which company was that?
Maybe we were just unlucky back then and contacted the most expensive drilling contractor. The other companies were just different heat pump manufacturers. I was mistaken there; after the first quote from Baugrund Süd, I didn’t compare further, assuming they were all similarly priced. Perhaps that was my mistake!
Anyway, that’s history now, and we are happy with the air source heat pump, but the topic occupied my thoughts a lot back then.
The drilling you mentioned is certainly interesting – which company was that?
Maybe we were just unlucky back then and contacted the most expensive drilling contractor. The other companies were just different heat pump manufacturers. I was mistaken there; after the first quote from Baugrund Süd, I didn’t compare further, assuming they were all similarly priced. Perhaps that was my mistake!
Anyway, that’s history now, and we are happy with the air source heat pump, but the topic occupied my thoughts a lot back then.
toxicmolotow schrieb:
Where do you all live, or where do you have to drill through obsidian? Our 100 meters (330 feet) of drilling cost about 5000 euros. Maybe it depends on the package (see my first post here). It's also funny that the drilling company matters a lot. My neighbor, who was the last to build here, couldn’t complete a borehole right next door (the companies “only” did water flushing). Maybe that’s why I didn’t get the cheapest, but in the end a drilling company that was economical for me.
@Bookstar Coefficient of performance (COP) over the year: many factors come into play here (location, domestic hot water, heating and ventilation behavior). I know many who lose a lot of COP due to hot water use and “lack of attention,” but most don’t care (“it’s just a few euros”). Still, there are databases online with real-world heat pump performance data (with hundreds of units) – for air-to-air heat pumps, a COP of 3.5 is really an absolute top value. So your comment calling it “really terrible” is quite exaggerated. Just look at the data for COP for domestic hot water or heating supply temperature of about 35°C (95°F) at subzero temperatures. By the way, do you have a heat meter?
I have optimized my system for my ground-source heat pump and, thanks to a lucky borehole, still have roughly 5°C (41°F) brine inlet temperature after two months below 0°C (32°F) outside. As a result, my ground-source heat pump always operates with a COP greater than 5. These 2–3 months per year actually account for two-thirds of my total annual heating and hot water costs.
T
toxicmolotof19 Mar 2018 23:36Saruss schrieb:
Maybe it depends on the package (see my first post here). (Probably more on the region and the ground conditions)Yes, there are certainly differences, but in our case, proper drilling was done, not flushing; the pipeline runs into the house, was pressure-tested, specially sealed (due to the water protection zone), filled, and all the bureaucratic requirements from the authorities were met. I don’t know what else would need to be included in such a package to make it “more valuable.” But it doesn’t help. I just wanted to provide a counterpoint to the 13,000 or 15,000 euros mentioned here.
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