ᐅ Heating System Question for New Build KfW 70: Air Source Heat Pump + Solar, Ice Storage?
Created on: 24 Feb 2015 11:42
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hiasl86
Hello dear forum users!
We are currently planning a new build in southern Bavaria near the border with Salzburg. At the moment, we are looking for the right heating system for our home. We have a living area of about 140 sqm (1507 sq ft). We plan to build to KfW 70 standard (36 cm (14 inch) bricks with perlite filling).
What we definitely do not want is oil heating. Gas is also not an option for us since there is no connection available, and I do not want to have a gas tank buried in the garden. We also don’t really want a pellet heating system because of the required storage space.
We are actually leaning towards a heat pump. We initially wanted geothermal energy with a deep borehole (ground collectors are not feasible due to limited land area). We received an offer for the deep drilling, but to me, it seems very expensive (12,000 - 15,000 Euro). The problem is that the water management authority limits the drilling depth to 10 m (33 ft). This is partly because sulfate rock was found nearby at depths of 30–40 m (98–131 ft), and no drilling has been done directly in our neighborhood yet. The drilling company suggested drilling 9 times to 10 m (33 ft) as a safe option. The less certain option (1. due to permits and 2. because it is unclear how far you can actually drill) would be 4 times 23 m (75 ft).
Now we might consider switching to an air-to-water heat pump with solar support (for domestic hot water and heating assistance). What do you think about this combination? How effective is it and what about electricity consumption? How well do air-to-water heat pumps perform in winter on very cold days? What investment costs should we expect roughly?
We also came across the solar heat pump system, combining solar, air, heat pump, and ice storage. Has anyone had experience with such a system? How does it perform in winter? Is it possible that you might end up heating only with electricity if the ice storage freezes too early and cannot thaw quickly enough, or is the solar and air energy usually sufficient? What about investment costs—how much higher are they compared to the solar plus air-to-water heat pump version?
I have browsed quite a few forums looking for answers and experiences with ice storage. Opinions seem quite divided (too early freezing, not cost-effective due to high investment costs).
Thank you in advance for your help and advice!
Best regards
Matthias
We are currently planning a new build in southern Bavaria near the border with Salzburg. At the moment, we are looking for the right heating system for our home. We have a living area of about 140 sqm (1507 sq ft). We plan to build to KfW 70 standard (36 cm (14 inch) bricks with perlite filling).
What we definitely do not want is oil heating. Gas is also not an option for us since there is no connection available, and I do not want to have a gas tank buried in the garden. We also don’t really want a pellet heating system because of the required storage space.
We are actually leaning towards a heat pump. We initially wanted geothermal energy with a deep borehole (ground collectors are not feasible due to limited land area). We received an offer for the deep drilling, but to me, it seems very expensive (12,000 - 15,000 Euro). The problem is that the water management authority limits the drilling depth to 10 m (33 ft). This is partly because sulfate rock was found nearby at depths of 30–40 m (98–131 ft), and no drilling has been done directly in our neighborhood yet. The drilling company suggested drilling 9 times to 10 m (33 ft) as a safe option. The less certain option (1. due to permits and 2. because it is unclear how far you can actually drill) would be 4 times 23 m (75 ft).
Now we might consider switching to an air-to-water heat pump with solar support (for domestic hot water and heating assistance). What do you think about this combination? How effective is it and what about electricity consumption? How well do air-to-water heat pumps perform in winter on very cold days? What investment costs should we expect roughly?
We also came across the solar heat pump system, combining solar, air, heat pump, and ice storage. Has anyone had experience with such a system? How does it perform in winter? Is it possible that you might end up heating only with electricity if the ice storage freezes too early and cannot thaw quickly enough, or is the solar and air energy usually sufficient? What about investment costs—how much higher are they compared to the solar plus air-to-water heat pump version?
I have browsed quite a few forums looking for answers and experiences with ice storage. Opinions seem quite divided (too early freezing, not cost-effective due to high investment costs).
Thank you in advance for your help and advice!
Best regards
Matthias
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DerBjoern24 Feb 2015 16:17To estimate which heating system is appropriate, you first need to determine the building's heating load. Making a decision based on a rough estimate often backfires...
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Sebastian7925 Feb 2015 21:44I think 1300 euros is not a small amount for the relatively small heated area. Euro figures alone don’t say much; you should rather specify the kW consumption.
Also, a 1.6 kW heat pump? What kind of model is that supposed to be? Especially since that will never work in winter – there is virtually no solar gain then.
And when do you use the heating? Exactly, in winter...
Also, a 1.6 kW heat pump? What kind of model is that supposed to be? Especially since that will never work in winter – there is virtually no solar gain then.
And when do you use the heating? Exactly, in winter...
Cascada schrieb:
...
It’s a similar situation with photovoltaics. High self-consumption in practice is not possible without battery storage – and output is low in winter. For a photovoltaic system financed by a third party including interest, insurance, repairs, reserves, etc., it is certainly no longer economically worthwhile.Photovoltaics are always worthwhile, regardless of whether you have a heat pump. High self-consumption is achievable even without a battery; at home, we reach 39%. This means you save 39% of your electricity consumption at about 27 cents/kWh and replace it with your own photovoltaic electricity that costs only around 10 cents/kWh. Bank interest rates are low anyway, insurance costs less than 50 euros/year, and there are no repairs since there are no moving parts except for the inverter every 10–18 years. What reserves for?
With a heat pump, self-consumption can only increase, and the 10 cents for photovoltaic electricity is cheaper than any heat pump tariff. Also, heat water preferably only at midday to further increase self-consumption. Only in December and January are yields low; from February to November, photovoltaics provide strong contributions.
Where do the 10 cents come from? They just seem to be "falling from the sky" right now. In relevant photovoltaic forums, different figures can be found compared to yours. Many also don’t manage to achieve such high E.V. values so easily; especially if, for example, they work during the day (and therefore have to heat water in the evening and generally need more electricity then)...
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