ᐅ Hydrogeological Report – Geothermal Energy, Air-to-Water Heat Pump, or Ice Storage?
Created on: 13 Jul 2022 17:36
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FCBenne04
Good evening everyone,
We want to replace our gas heating system, which is over 30 years old, with a new one. Additionally, we plan to remove the traditional radiators and install underfloor heating throughout the entire house. We were thinking of milling the pipes into the existing screed, unless a complete renovation with new screed, etc., would be more sensible?
1) Hydrogeological Expert Report: We had considered a geothermal heat pump (ground source heat pump) as the heating option. However, since the building is located in a water protection area, a hydrogeological expert report is required to assess whether geothermal energy is permitted and to what extent (depth, brine, number of boreholes). The water authority is very strict about this. I have attached the information sheet with the requirements for the report.
Have you ever heard of such a hydrogeological expert report, and do you know what the costs might be? We really have no idea how to estimate this and wanted to ask if anyone has had similar experiences.
2) Comparison of Air-to-Water Heat Pump and Geothermal Systems: These two systems are often compared. One person says one thing, another says something else. But I haven’t found or heard any clear facts yet. Geothermal is said to be more efficient, but air-to-water heat pumps have become very powerful and therefore potentially more cost-effective. The trend seems to be towards air-to-water heat pumps, which are somewhat cheaper to install than geothermal systems. Prices have increased significantly everywhere recently. Could someone provide us with more detailed information on this topic to help with our decision?
3) Ice Storage Heating: The heating/well installer even suggested an ice storage heating system as an alternative because it does not require a permit. However, I don’t know anyone who uses such a heating system. What do you think about this?
Thank you very much for your help and best regards!
We want to replace our gas heating system, which is over 30 years old, with a new one. Additionally, we plan to remove the traditional radiators and install underfloor heating throughout the entire house. We were thinking of milling the pipes into the existing screed, unless a complete renovation with new screed, etc., would be more sensible?
1) Hydrogeological Expert Report: We had considered a geothermal heat pump (ground source heat pump) as the heating option. However, since the building is located in a water protection area, a hydrogeological expert report is required to assess whether geothermal energy is permitted and to what extent (depth, brine, number of boreholes). The water authority is very strict about this. I have attached the information sheet with the requirements for the report.
Have you ever heard of such a hydrogeological expert report, and do you know what the costs might be? We really have no idea how to estimate this and wanted to ask if anyone has had similar experiences.
2) Comparison of Air-to-Water Heat Pump and Geothermal Systems: These two systems are often compared. One person says one thing, another says something else. But I haven’t found or heard any clear facts yet. Geothermal is said to be more efficient, but air-to-water heat pumps have become very powerful and therefore potentially more cost-effective. The trend seems to be towards air-to-water heat pumps, which are somewhat cheaper to install than geothermal systems. Prices have increased significantly everywhere recently. Could someone provide us with more detailed information on this topic to help with our decision?
3) Ice Storage Heating: The heating/well installer even suggested an ice storage heating system as an alternative because it does not require a permit. However, I don’t know anyone who uses such a heating system. What do you think about this?
Thank you very much for your help and best regards!
D
Deliverer14 Jul 2022 11:00I agree with k-man: Older, larger houses often come with a substantial garden. In such cases, if the ground temperature is below -12°C (10°F), it’s worth considering a horizontal ground source heat pump (HGSP). Installing trench collectors yourself is relatively straightforward, which can save additional costs.
Unless you live in the mountains, there are very few homes that can’t be operated effectively with a modern R290 heat pump.
Of course, this assumes the house is reasonably well maintained. If no renovations have been done for 30 years, the property will need refurbishment. But that’s unrelated to the heating system and needs to be done anyway. Ideally, this should be done before replacing the heating system, as otherwise the heat pump may end up oversized for efficient operation.
Unless you live in the mountains, there are very few homes that can’t be operated effectively with a modern R290 heat pump.
Of course, this assumes the house is reasonably well maintained. If no renovations have been done for 30 years, the property will need refurbishment. But that’s unrelated to the heating system and needs to be done anyway. Ideally, this should be done before replacing the heating system, as otherwise the heat pump may end up oversized for efficient operation.
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FCBenne0415 Jul 2022 14:51Axolotl2022 schrieb:
What about facade insulation, insulation of the basement ceiling / roof / upper floor ceiling, new windows, etc.?
Just underfloor heating plus a heat pump doesn’t automatically mean low heating costs.
What does the room-by-room heating load calculation say?
I find that more useful because it allows for more flexible installation (different (larger) pipe sizes and spacing—a heat pump requires flow, flow, and flow) and it doesn’t really cost more. Keep in mind that not only the heating system itself but also the related work is often subsidized.
Both systems actually work very well. Assume that you will probably never recover the extra investment in geothermal energy during your lifetime (due to drilling costs, it is often tens of thousands of euros more expensive than a "simple" air-to-water heat pump. Far from "somewhat cheaper"). The higher efficiency means heating costs of €47 instead of €50 per month with the air-to-water heat pump in a new build.
Uncommon but apparently works. In over 20 years in the construction (financing) industry, I have never seen it in practice. The combination of geothermal and ice storage is by far the most expensive option (the ice storage alone might cost five figures—additional to that). As far as I know, it is suitable for buildings with very high heating and cooling demand—mainly commercial properties.Thank you very much for your assessment! The building was constructed in 1995. We have considered insulating the basement ceiling and possibly insulating the roof again. It is not a classic, large old building. We were not planning to replace the windows just yet.
Then we need to review the underfloor heating again and maybe get a quote for a new screed.
Is it possible to carry out a room-by-room heating load calculation yourself, or do you need a professional for that?
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FCBenne0415 Jul 2022 14:52WilderSueden schrieb:
Yes, of course. The worse the house’s condition, the sooner the extra cost for geothermal heating pays off. Therefore, the current energy consumption as well as the expected one after renovation would be important.
It would also be relevant to know the area where the house is located and the typical winter temperatures. The current energy consumption (gas) is about 25,000 kWh per year. The living area is approximately 125 m² (1,345 sq ft). The house is detached. Winter temperatures typically reach between -10 and -15°C (14 and 5°F).
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FCBenne0415 Jul 2022 14:58k-man2021 schrieb:
We are also building in a water protection area and planning to use a brine heat pump. Deep drilling is not permitted, but horizontal ground collectors are allowed. I spoke with the local water authority, and it was actually quite straightforward… there are a few requirements regarding the installation depth (x meters above the groundwater level), pressure monitoring of the brine circuit to detect leaks (easy), and specifications for the brine itself (also easy). Connection must be done by a certified installer, that’s about it as far as I remember.
We are planning a horizontal closed-loop collector (trench collector).
A hydrogeological report is usually related to the groundwater level, but we don’t need one because the collector is installed at a maximum depth of 2m (6.5 ft) and our groundwater is much deeper. Hello k-man, thank you very much for your input! I have honestly never heard of the horizontal closed-loop collector before. It definitely sounds like an interesting alternative. However, the plot is only about 380 m² (4,090 sq ft) in size. The undeveloped (garden) area around the house is about 120 m² (1,292 sq ft). Is that enough space to use this method? I assume there also need to be setback distances from the neighbor’s property and the house itself.
Also, is the horizontal closed-loop collector eligible for subsidies (e.g., 35% BAFA funding) just like geothermal and air-to-water heat pumps? I suppose any personal labor wouldn’t qualify for funding?
Thanks in advance for your feedback.
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Axolotl-neu15 Jul 2022 14:59FCBenne04 schrieb:
The current energy consumption (gas) is about 25,000 kWh per year.With the current gas price, that means around €6,500 in heating costs. 200 kWh per sqm (20,000 BTU per sqft).I would controversially claim that every euro spent on a new heating system is wasted money (especially when unconventional options like ice storage are suggested) if nothing is done to optimize the building’s energy consumption.
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FCBenne0415 Jul 2022 15:00Deliverer schrieb:
I agree with k-man: In older, larger houses, there is often a sizable garden as well. In such cases, you should consider horizontal ground source heat pumps (HGSP) when the natural ground temperature is below -12°C (10°F). Loop trench collectors can be installed quite easily by yourself, which can save additional costs.
If you don’t live in a mountainous area, there are hardly any houses that cannot be reasonably operated with a modern R290 heat pump.
Of course, this assumes the house is reasonably well maintained. If nothing has been done for 30 years, renovation is necessary. But that’s not related to the heating system; renovation needs to be done anyway. Ideally, it should take place BEFORE replacing the heating system; otherwise, the heat pump will end up being oversized for efficient operation. Hello Deliverer,
thank you for your assessment. As mentioned above, unfortunately we do not have a large garden. What do you mean by WWWP?
The house was built in 1995. No energy-related renovation has been done so far, so from an energy perspective, almost 30 years nothing has really been improved. Is that a problem?
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