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:
Based on what has been posted here, I was probably not wrong in saying that geothermal energy with drilling is not economically viable in southern Germany. Especially since modern air-to-water heat pumps now achieve a COP of over 4, which further worsens the payback period for geothermal systems. On top of that, modern units have significantly reduced noise emissions. Even mine can only be heard when you stand right next to it.
It’s a shame, really a great technology, but no longer practical so easily! That is still a bit too general.
In particular, the COP alone tells you very little. For most air-to-water heat pumps, the value is often given for A7W35, meaning a lift from 7 degrees Celsius (45°F) outside temperature to 35 degrees Celsius (95°F) water temperature. However, this is not particularly relevant for the annual performance factor since hot water temperatures are higher than 35 degrees Celsius (95°F), and at 7 degrees Celsius (45°F) outside temperature, the heating demand is still quite low.
The list from BAFA with air-to-water heat pumps, updated this March, includes more than 500 models and shows an average COP under 4 for A2W35, with only a few models exceeding 4. The highest I have seen is around 4.42, but that was for a 13 kW unit, which is far too large for a single-family home nowadays. Generally, the smaller the capacity, the lower the COP tends to be.
toxicmolotow schrieb:
Well, I don’t know how it is in other states, but NRW has a portal worldwideweb.geothermie.nrw.de *cough* where you can check the probable extraction capacity at a drilling location. I guess there are similar resources everywhere.
Honestly, I didn’t know such maps existed—it’s almost like checking mobile network coverage…
I looked it up, and there is something similar for our state as well… okay, so that’s the reason: medium to rather poor.
Thanks for the info, now I can sleep peacefully knowing that geothermal energy probably doesn’t make sense for me… what a shame.
T
toxicmolotof20 Mar 2018 22:02Well,
@Jana33
That’s just my amateur opinion, but if you need twice as many meters of drilling for the same output, it eventually becomes uneconomical. Would a trench collector possibly make sense?
@Bookstar
The south is often colder in winter compared to, for example, here in the Lower Rhine region. So, I’m not sure I would want an air-to-water heat pump in the deep Allgäu area. On the other hand, the Rhine Rift Valley might be quite suitable for deep geothermal energy. The yield isn’t equally good or bad everywhere within a state. There can be significant differences in some cases.
And to round this off for everyone… if groundwater is nearby, it’s worth checking whether a groundwater heat pump could make sense. There are good concepts for this as well, provided the site is suitable.
@Jana33
That’s just my amateur opinion, but if you need twice as many meters of drilling for the same output, it eventually becomes uneconomical. Would a trench collector possibly make sense?
@Bookstar
The south is often colder in winter compared to, for example, here in the Lower Rhine region. So, I’m not sure I would want an air-to-water heat pump in the deep Allgäu area. On the other hand, the Rhine Rift Valley might be quite suitable for deep geothermal energy. The yield isn’t equally good or bad everywhere within a state. There can be significant differences in some cases.
And to round this off for everyone… if groundwater is nearby, it’s worth checking whether a groundwater heat pump could make sense. There are good concepts for this as well, provided the site is suitable.
Saruss schrieb:
It’s still a bit too general. Especially, the COP says very little. For most air-to-water heat pumps, the COP is often given for A7W35, meaning from 7°C (45°F) outside temperature to 35°C (95°F) water temperature. However, this is not very relevant for the seasonal performance factor (SPF), since domestic hot water is hotter than 35°C (95°F), and at 7°C (45°F) outside temperature, heating demand is still quite low.
The BAFA list of air-to-water heat pumps, updated this March, with more than 500 models, shows an average COP under 4 for A2W35, with only a few models above 4. The highest I’ve seen is about 4.42, but that was for a 13 kW unit, which is far too big for a typical single-family home nowadays. Generally, the smaller the output, the lower the COP tends to be.
I calculated it using the seasonal performance factor calculator from Novelan, and with the latest generation inverter technology, you get about 4.2. I assumed 25% domestic hot water demand.
Bookstar schrieb:
I calculated it using the annual performance factor calculator from Novelan, and for the latest generation with inverter technology, it comes to 4.2. I assumed 25% domestic hot water demand.Well, that’s theoretical, and from a manufacturer of the units. The fact is that the basic concept and physics are the same for air-to-water heat pumps and ground-source heat pumps; only the heat source differs. So, better heat pumps don’t fundamentally change anything, especially since there are now ground-source heat pumps with variable capacity as well.Otherwise, I find it hard to imagine a real annual performance factor that high for an air-to-water heat pump, since domestic hot water is produced with very low COPs, and—at least here in this region and in my house—75% of the annual energy demand occurs during the 3 coldest months, when the air is cold enough to result in COPs well below 4 (for air). Currently, nighttime temperatures here are only around -5°C (23°F), but my ground-source heat pump achieves a COP of over 6 thanks to the low design temperature of the heating system (this is a current value; I have the heat pump’s performance charts for reference).
M
Mastermind121 Mar 2018 21:24Bookstar schrieb:
I calculated it using the annual performance factor calculator from Novelan, and for the latest generation with inverter technology, it comes out to 4.2. I assumed 25% hot water demand.Annual performance factor calculators are useful... but I would put more emphasis on practical experience. There is a heat pump consumption database where you can make rough comparisons. This also includes heat pumps that may not be optimally configured or installed. However, it reflects reality better than manufacturers’ own calculators.For example, there are practical values from the currently very popular Panasonic Geisha (Aquaera). Interestingly, these are often heat pumps installed by the owners themselves.
Therefore, today I would rather consult an HVAC technician than a heating engineer if you want a heat pump and cannot or do not want to do any work yourself. For inspection and subsidies from BAFA, a specialist contractor’s declaration is required, and the BAFA application must be submitted before placing the order.
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