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.
1. How about checking the information? It’s all here in the forum. I believe I have shared details about my building project far more thoroughly here than most others would dare to do. What you’re asking for requires less effort than the amount of information you demand yourself (just the name of a voluntary energy consumption database…)… for example, click on “Page 1”—or is that already asking too much? Jokester!
2. Your "delivery" (which doesn’t even match the source you mentioned) of the 20% difference is extremely rough, and your calculations are very minimalistic. You take some guessed monthly value and arbitrarily reduce it by 20%. That’s not objective, especially not the generalizations you’re making.
2. Your "delivery" (which doesn’t even match the source you mentioned) of the 20% difference is extremely rough, and your calculations are very minimalistic. You take some guessed monthly value and arbitrarily reduce it by 20%. That’s not objective, especially not the generalizations you’re making.
B
boxandroof28 Oct 2019 17:41Construction costs and planning quality are crucial for cost-efficiency.
The slightly better efficiency of a ground-source heat pump compared to a good air-to-water heat pump makes little difference in operating costs for houses with less than 10,000 kWh (34,100 BTU) heating demand. Simple assumptions are more than enough to calculate this adequately. I don’t understand all the fuss here.
The worse the building quality, the colder the region, and the cheaper the borehole, the more ground-source heat pumps make sense. Not to mention the benefits like passive cooling or the absence of an outdoor unit.
The slightly better efficiency of a ground-source heat pump compared to a good air-to-water heat pump makes little difference in operating costs for houses with less than 10,000 kWh (34,100 BTU) heating demand. Simple assumptions are more than enough to calculate this adequately. I don’t understand all the fuss here.
The worse the building quality, the colder the region, and the cheaper the borehole, the more ground-source heat pumps make sense. Not to mention the benefits like passive cooling or the absence of an outdoor unit.
Glad you’re opening up personally… but you really don’t have to, so please don’t. Still, thanks for the note about the first page.
Next, using your data and some conservative estimates for an air-to-water heat pump:
You used 2000 kWh from September to September with a seasonal performance factor (SPF) of 5.5. Let’s assume a less efficient air-to-water heat pump with an SPF of 3.5. With that, you’re looking at roughly 35% more electricity consumption.
At my electricity cost of 25 cents per kWh, that means an additional 700 kWh per year, which comes to about €175 (approximately $190) annually. Over ten years, that adds up to €1750 (approximately $1900).
Now here’s the kicker: over 60 years, that extra cost would exceed your €10,500 (approximately $11,400) investment for the borehole.
Calculate it however you like, but realistically, drilling a borehole only pays off very late—if at all.
Edit: this applies to new builds and proper planning.
Next, using your data and some conservative estimates for an air-to-water heat pump:
You used 2000 kWh from September to September with a seasonal performance factor (SPF) of 5.5. Let’s assume a less efficient air-to-water heat pump with an SPF of 3.5. With that, you’re looking at roughly 35% more electricity consumption.
At my electricity cost of 25 cents per kWh, that means an additional 700 kWh per year, which comes to about €175 (approximately $190) annually. Over ten years, that adds up to €1750 (approximately $1900).
Now here’s the kicker: over 60 years, that extra cost would exceed your €10,500 (approximately $11,400) investment for the borehole.
Calculate it however you like, but realistically, drilling a borehole only pays off very late—if at all.
Edit: this applies to new builds and proper planning.
I also see that the 25 years can reasonably be questioned without the original poster taking it personally.
Let me consider my own situation:
Air-to-water heat pump + photovoltaic system, about 2200 kWh electricity with a performance factor (COP) of 4.5. Around 1400 kWh cost me 25 cents, 800 kWh 11 cents (lost feed-in tariff), which makes 440€/year. Simplified with a seasonal performance factor (SPF) of 5.5, this is about 360€, meaning an annual saving of 80€.
Over 25 years, this amounts to an advantage of 2000€, which wouldn’t even cover the additional costs for a ground-source heat pump.
No doubt, geothermal energy is a great option and I would have chosen a horizontal ground collector if space had allowed. Economically, however, it is at best viable in an Alpine village, and even then only with a lot of luck.
Let me consider my own situation:
Air-to-water heat pump + photovoltaic system, about 2200 kWh electricity with a performance factor (COP) of 4.5. Around 1400 kWh cost me 25 cents, 800 kWh 11 cents (lost feed-in tariff), which makes 440€/year. Simplified with a seasonal performance factor (SPF) of 5.5, this is about 360€, meaning an annual saving of 80€.
Over 25 years, this amounts to an advantage of 2000€, which wouldn’t even cover the additional costs for a ground-source heat pump.
No doubt, geothermal energy is a great option and I would have chosen a horizontal ground collector if space had allowed. Economically, however, it is at best viable in an Alpine village, and even then only with a lot of luck.
A coefficient of performance (COP) of 4.5 for an air-to-water heat pump is more the exception than the rule. If you look at the heat pump consumption database, the ratio is usually around 1:1.3 in favor of geothermal systems. For a heating demand of 10 kW, this results in an overall advantage of approximately 4,800 euros over 25 years. If you include government subsidies like those from BAFA, the total benefit can quickly approach 10,000 euros.
Therefore, I don’t consider a 25-year period to be unrealistic, especially when factoring in subsidies. I also see the drilling as a value-adding measure, which should not be overlooked.
Therefore, I don’t consider a 25-year period to be unrealistic, especially when factoring in subsidies. I also see the drilling as a value-adding measure, which should not be overlooked.
Cost of trench collector under €2,500; subsidy €4,500. Compared to an air-to-water heat pump, this means saving money, plus lower ongoing heating costs. The passive cooling alone is invaluable, and there’s no annoying outdoor unit... Annual performance factor >5.5...
Simple calculation, since the trench collector was built as a DIY project... I know. But including planning, it took less than 3 days.
Simple calculation, since the trench collector was built as a DIY project... I know. But including planning, it took less than 3 days.
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