ᐅ BAFA Innovation Grant for Air Source Heat Pumps

Grantlhaua schrieb:
For example, in combination with its solar system. Even with a larger photovoltaic system, the storage can serve as an additional energy buffer if no battery is available.

Solar thermal plus heat pump is a rather suboptimal combination. Generally, solar thermal increases the heat generation costs (see BDEW heating cost comparison). A more sensible option is a heat pump combined with photovoltaic. You don’t actually need storage for photovoltaic surpluses. Firstly, these surpluses rarely occur during the heating season, and secondly, screed (even better, underfloor heating screed) can store additional heat much more effectively than a conventional buffer tank. Stratified storage also has a major drawback when used with a heat pump. Due to its design, the heating system ends up cannibalizing the domestic hot water. Because the hot water is produced at a higher temperature but with a lower COP, this results in an overall lower seasonal performance factor for the system. In general, a heat pump should charge the underfloor heating directly (without a buffer). Fraunhofer has conducted relevant studies supporting this.

Grantlhaua schrieb:
An alternative would have been the IDM, but I can get the Kermi at a very good price.
[...]
We can get it, but then you would need a seasonal performance factor calculation, right? Where do you get that from?

You can calculate the Kermi’s seasonal performance factor yourself. Unfortunately, the Kermi is rather average and only reaches a seasonal performance factor of 4.24 at a flow temperature of 30°C (86°F). The other Kermi models don’t seem any better. Even reducing the share of domestic hot water doesn’t bring it into a reasonable range.
So it might be worth considering the more expensive IDM and then receiving €2,500 (about $2,700) BAFA funding, which might even make it cheaper than the Kermi. The IDM iPump A2-7 reaches 4.51 at
Flow temperature = 30°C (86°F) (which should possibly be achievable with a bathroom heat recovery unit)
Heating limit temperature = 12°C (54°F)
NAT = -14°C (7°F)
I have a Nibe myself, but I personally prefer the IDM…
You can do the calculation yourself, but the signature must come from someone with the relevant expertise. It doesn’t have to be your builder. Many homeowners have relevant qualifications based on their education. You might have to prove this expertise to BAFA if needed.

Regardless of funding, wall heating in the bathroom also increases comfort. Thanks to the pleasant radiant heat, the air temperature can be kept around 22°C (72°F). The warmth then feels like 24°C (75°F) air temperature.

Best regards
Nika

gnika77 schrieb:
So it might be worth considering the more expensive IDM and then receive a €2500 BAFA subsidy, which might even make it cheaper than using Kermi.

Isn't the maximum €2000 only?

And how do you prepare the domestic hot water then? A fresh water station needs a certain buffer to draw heat from, doesn't it?

Grantlhaua schrieb:
That’s how I understand it too, but wouldn’t you need a calculation of the system efficiency for that?

Yes and no... For air source heat pumps, essentially only a system concept is subsidized...
[Quote=https://WWW.BAFA.de/SharedDocs/Downloads/DE/Energie/ee_waermepumpen_innovationsfoerderung_anlagenkonzepte.pdf?__blob=publicationFile&v=3]
2. Air-to-water heat pump with supplementary heat source solar radiation
Combination of an eligible air-to-water heat pump with the supplementary heat source solar radiation. The collectors used must be eligible according to the applicable guidelines. They must be integrated in such a way that an increase in the heat source temperature and thus an improvement in the heat pump’s efficiency is achieved. The collector output must be at least one third of the standard heating load of the building being supplied.
The following additional conditions apply:
For the collectors used, a heating output of 0.2 kW per m² (square meter) of gross collector area may be assumed.

• The bivalence temperature must not be above -6°C (21°F), unless the heated building has a system for providing heat from biomass.
• For (hybrid) heat pumps where, due to their design, the use of electric heating elements is excluded, the bivalence point must not exceed 0°C (32°F).
• A minimum system seasonal performance factor (SPF) of 3.9 must be demonstrated. This proof is provided by submitting a simulation calculation.

[/Quote]
In my opinion, this system concept is technical and financial overkill. The subsidy doesn’t even really cover the additional costs. I would rather skip the subsidy and simply install photovoltaic panels. The benefit of photovoltaics on the same area is significantly higher. Also, photovoltaics fully pay for themselves. The photovoltaic system could cover about 30% of the heat pump’s energy demand, supply other devices with electricity, and any surplus is additionally compensated. Overall, this is much more economical than the oversized solar thermal system from the system concept.

Best regards
Nika

That’s probably how we’ll do it. We are going to install a photovoltaic system on the garage anyway. The additional solar panels would have been installed on the house roof.

Grantlhaua schrieb:
Isn't the maximum amount just 2000€?

And how do you prepare domestic hot water then? A domestic hot water station needs a certain buffer from which it can draw heat, right?

2000€ is correct. I was also thinking about a storage tank (ST). There is no 500€ combined bonus for that. But as mentioned before, a heat pump plus a storage tank is counterproductive. So in fact, it would indeed be "only" 2000€.

Regarding the domestic hot water station:
1. The remark that a buffer is counterproductive refers to the heating buffer tank. For domestic hot water, of course, you need a domestic hot water buffer, such as a "standard" hot water storage tank, a tank with continuous flow function, or even a domestic hot water station. Which one makes the most sense depends on personal preferences and requirements. I prefer as simple solutions as possible, so rather a "standard" hot water storage tank. I did not explicitly list combined buffer tanks because they are an efficiency killer with heat pumps.

2. Personally, I do not find a domestic hot water station (DHW station) optimal with a heat pump since it requires two heat exchangers for heat transfer overall. A properly sized hot water tank would be more efficient. Nevertheless, a DHW station also has advantages. There are heat pump specialists who rate the advantages of a DHW station significantly higher than the disadvantages of the second heat exchanger. IMHO, everyone should decide this according to their own preferences/needs/requirements. As long as the additional cost of a DHW station is not too high, from my point of view there is no significant objection to it.

Regards, Nika

Grantlhaua schrieb:
The additional solar system was supposed to be installed on the house roof.

I recommend carefully calculating the economic efficiency of the solar thermal system. In general, forgoing it tends to be more cost-effective than installing it. Exception: high subsidies. However, even with significant subsidies, photovoltaic systems are usually more profitable. Therefore, it might be more sensible to install photovoltaic panels on the house roof, if anything at all...

Regards, Nika