ᐅ Photovoltaic System and Air-to-Water Heat Pump – Profitability for a Single-Family Home Built to KfW 55 Energy Efficiency Standard
Created on: 11 Jan 2022 23:19
M
Maxwell8
Hello,
we are building a fairly large KFW55EE house with external dimensions of approximately 10x14m (33x46 feet) and a roof pitch of 15° (roof surfaces facing north and south).
We have a lot of window area (100m2 (1,076 sq ft)) and expect an energy consumption of about 7-9k kWh per year due to the size.
Heating is provided by underfloor heating with the Tecalor THZ 504 air-to-water heat pump.
Feed-in tariffs are no longer significant, but the electricity price is currently 45 cents/kWh.
We would have to finance the photovoltaic system ourselves because there is no sufficient budget left.
> From a profitability perspective, does a photovoltaic system make sense in our situation?
> What size and costs should we expect?
> Should it be installed directly or should we first prepare with conduits?
> We also have an attached 6x6m (20x20 feet) flat-roof garage on the east side. Would adding photovoltaic panels there be beneficial?
I will, of course, speak with companies but would like to gather some opinions beforehand.
Thank you in advance. 🙂
we are building a fairly large KFW55EE house with external dimensions of approximately 10x14m (33x46 feet) and a roof pitch of 15° (roof surfaces facing north and south).
We have a lot of window area (100m2 (1,076 sq ft)) and expect an energy consumption of about 7-9k kWh per year due to the size.
Heating is provided by underfloor heating with the Tecalor THZ 504 air-to-water heat pump.
Feed-in tariffs are no longer significant, but the electricity price is currently 45 cents/kWh.
We would have to finance the photovoltaic system ourselves because there is no sufficient budget left.
> From a profitability perspective, does a photovoltaic system make sense in our situation?
> What size and costs should we expect?
> Should it be installed directly or should we first prepare with conduits?
> We also have an attached 6x6m (20x20 feet) flat-roof garage on the east side. Would adding photovoltaic panels there be beneficial?
I will, of course, speak with companies but would like to gather some opinions beforehand.
Thank you in advance. 🙂
Maxwell8 schrieb:
Thanks for the answers, sounds good.
No air conditioning, but ventilation yes. A charging station in the garage will also be installed, hopefully the KfW subsidy will be available again. I can charge for free at work anyway.
Bidirectional would be nice, then I’d have a 60+kWh battery, but the charging stations are still way too expensive. 😉 That would be nice, then you could basically take the electricity from work home with you 😉
The Kia EV6 can supply 3.6 kW (3.6 kW) from the battery (about 77 kWh (77 kWh)). So you could at least cover your house’s basic load at night.
It’s possible, but unfortunately not politically supported (yet) and is therefore "forbidden."
WilderSueden schrieb:
In winter, you generally won’t get much from the photovoltaic system. In good weather, you’ll be heating with solar gains and will likely end up too warm rather than too cold. In bad weather, photovoltaic generates relatively little electricity compared to the heat pump. The low roof pitch further reduces efficiency in winter.
For profitability, the crucial factor is whether you can use the electricity in summer. In other words, are you home during the day?
With bidirectional charging, the same question applies: How often does the electric car leave in the morning and only return in the evening? Today was very cold, and I generated 38.5 kWh with my approximately 6.5 kWp (kilowatt peak) small system 🙂. Since I was home briefly in the afternoon and plugged in the BEV to “charge with the sun,” my self-consumption is a bit higher than usual. But that’s right, I have photovoltaic at home, and the car stays at the company 🙄. I always regret feeding electricity into the grid instead of charging the car. The next office starting in autumn will likely get two systems of 30 kWp each :p
We have several systems in the family—soon there will be six. That way, we have some comparisons regarding orientation and roof pitch.
A 45° (degree) pitch with south-facing orientation is probably more efficient in winter (when heating demand is highest). Otherwise, flatter pitches work better in summer (when cooling is desired or necessary), especially if both roof sides can be equipped.
D
Deliverer23 Feb 2022 20:04i_b_n_a_n schrieb:
It is possible, but unfortunately politically (still) not supported and therefore "prohibited" There will need to be a lot of progress in the coming years. So I have not given up hope yet.
Not least because VW is entering the business.
Deliverer schrieb:
A lot will need to change in the coming years. So I haven’t given up hope yet.
Not least because VW is entering the business. Slightly off-topic 😀 :p VW will no longer exist in the car market in 5-6 years at the latest. They were also involved in combined heat and power plants when they thought the market was ready. VW is easily about 5 years behind technologically, and not just behind Tesla. Speaking of Tesla, I paid for the Y today; it will be delivered on March 17. That will be the second company BEV alongside my "small" MX-30.