Air-water heat pump current consumption and data

I still need to read more deeply into the subject to save my father-in-law. He is still on the trip of not feeding in and achieving maximum autonomy with storage. However, he also knows someone who can get him the stuff very cheaply...

No, that's wrong.
For self-consumption systems with surplus feed-in (which most people probably have on their roofs), about 70% actually only makes sense from around 7kW module output with a south-facing orientation.

What else. Everything else would be rarely stupid even with storage. I have been feeding in almost every day since mid-February, despite storage and an electric car.
Now just imagine your system caps, without reason, 3 kWh per hour between 11 am and 1 pm, every day, for 4 months (roughly because not every day has full power sunshine).

You don’t want that just to save 300–400€ once.

I still have to read deeper into the subject to save my father-in-law. He is still on the trip of not feeding in and achieving maximum self-sufficiency with storage. However, he also knows someone who can get him the stuff very cheaply...

Instead of talking, you can also calculate it once. Since I wanted to supply the heat pump as well, I also calculated cloud solutions. And they were not worthwhile, or so marginal that a small change in the electricity price or cloud contract would turn everything anyway. And possibly the entrepreneurial use and thus the depreciation possibility is at risk. Systems also behave differently with small photovoltaic + large battery or vice versa, with and without heat pump connected, etc. Therefore calculate, also with/without tax benefits. Example with battery: 1 kWh capacity over 15 years at about 220 cycles p.a. (can also be higher or lower) would be 3300 cycles. If it saves me about €0.22/kWh with 5% losses (0.30 - 0.08), then a kWh may cost a maximum of €726. If it lasts longer (then at 90 and 80% capacity), that is fine. If the electricity price rises within 15 years, it goes faster too. If I can depreciate, preferably with Soli (because there is), it could even be €1300. So it depends. And nothing must break down for that long either.

No, storage systems are generally not recommended. They are economically nonsense, as they are still far too expensive (currently about a factor of 3 away from profitability) and ecologically bad, because they have to be produced with great effort and the stored amount of electricity PLUS the charging losses PLUS the operational losses are not available on the grid to displace coal power.

That could change in 10 years. But as of now, the only reason for a storage system is: hobby.

I agree on the ecological part. But a holistic view would be useful.

I don’t see the factor 3. Where does that come from? With depreciation (see my post about it) 1 kWh should already cost 1.3k€ net. More, if the electricity price actually rises or the device lasts longer than 15 years. After 3300 cycles, 90% capacity should still be expected. (more detailed analysis on Eigenwatt’s YouTube channel).

I enjoy it as a hobby (and it is hardly more expensive than some other hobbies), but it also has the psychological effect that I consistently switch off devices in the evening or even start the dishwasher and washing machine while the sun is shining. So I save a bit more due to this behavior or cause a longer service life.

(Before someone now comes to me with a Senec/Sonnen cloud storage brochure: No, their calculations are wrong.)

Correct. But most other modeling calculations are also designed for some normal consumer. With heat pumps or e-cars, it is off.

BUT: I can comfort everyone who is now sad because they wanted a storage system after all. Most of you already have one. Many even two. And in a few years, three or four.
These would be: hot water storage tank, screed, first and second car. You can easily shove 10 kWh of electricity into the first two. That should be enough well over the night. And there are no e-cars anymore under 50 kWh.
What the additional 5 to 10 kWh in the basement (for almost as many thousands) are supposed to achieve now... I don’t know.

The mostly well under 1 t water in the hot water storage tank (“stores” about 50-60 kWh per month, i.e. almost 2 kWh/day) is far behind the screed in “capacity”. But I partly don’t need that at all. So not available. Also I only save 0.12€ per kWh.

A bidirectionally charging e-vehicle would be the best storage for the house. Because for commuting to work we would need about 1.5-2 kWh per day here.

Example with battery: 1 kWh capacity over 15 years with about 220 cycles p.a. (can be higher or lower) would be 3300 cycles. Saves me about €0.22/kWh with 5% losses (0.30 - 0.08),

This calculation ignores that photovoltaic electricity also has a production cost and is not free. You will pay taxes on the stored energy. And you forgo feed-in tariffs if you consume the energy yourself.

Achieving 220 cycles is not easy. This requires a photovoltaic system that can charge the battery on 220 days per year and consumers who can draw this energy 220 times a year while the photovoltaic system is not producing (enough). You also need a battery with enough discharge power to cover these consumers as completely as possible.

There are also minor things like maintenance charging in winter, etc., that need to be included in the calculation.

I once estimated this elsewhere, you can look it up, but the result was: One kWh drawn from the battery costs 40 cents or more and is thus significantly above the purchase price from the power grid. It is a hobby!

As a hobby, I enjoy it (and it's hardly more expensive than some other hobbies), but it also has the psychological effect that I consistently turn off devices in the evening or run the dishwasher and washing machine while the sun is still shining. So through this behavior I save a bit more or cause a longer lifespan.

I completely agree and even go further. Without smart meters/inverters/photovoltaics, most people don't even know how much electricity their devices consume.

You might know that if you regularly go down to the basement/laundry room every two weeks, the meter has 200-300kWh more on it, but you don't think that the hairdryer consumes 1.7kWh, or that the dishwasher at 60 degrees for 2 hours consumes 2.4kWh (even though it has an A+++++ rating).
And when you see that the dishwasher consumes more than the heat pump, you seriously reconsider whether to turn it on in the evening without sun.