ᐅ Operating a heat pump independently with a photovoltaic system.
Created on: 18 Dec 2015 19:51
I
Inotsara
Is there a photovoltaic expert here? Preferably an engineer specializing in this field? I am an electrician myself but have not yet had any practical experience with photovoltaic systems. So far, I only know about them theoretically and am very enthusiastic. I want to dive deeper into this topic and prepare myself for practical work. Recently, I have been looking into inverters and especially battery storage. The more I read, the bigger the gap I feel needs to be filled.
Currently, I am working on a project involving my parents' air-to-water heat pump. It’s a newly built house with two living units. The combined electricity consumption of both units is about 2200 kWh. Additionally, the pump consumes approximately 6600 kWh per year. Naively, I assumed my parents could invest around 25,000€ in a 9 kWp photovoltaic system and achieve a self-sufficient setup with very low electricity costs (about 30€ per month instead of 180€).
But that’s not the case. Firstly, a single-phase storage system is not an option because, due to the technology and grid regulations, the pump relies on the other two phases and will ALWAYS draw power from the grid. Even with a three-phase battery storage system, this problem would only be theoretically circumvented but not completely solved. Especially in winter, the pump runs at 80%-100% capacity while a photovoltaic system generates only about 30%-35% of its output in winter. In summer, the situation is almost exactly the opposite. This means we would underproduce in winter and overproduce in summer. On top of that, a three-phase battery system costs twice as much, and the number of manufacturers offering this option is very limited.
So, my question to the real experts: Should I just discard the idea of making the heat pump fully independent, or have I missed something?
I have gained a lot of knowledge in recent days through phone conversations with an engineer who is also a salesperson. However, I feel a bit uncomfortable bothering him further. He has already explained a lot to me. Also, information in written form is always better because you can look things up repeatedly and add to your knowledge. Therefore, it would be great if we could share our knowledge here together =)
Currently, I am working on a project involving my parents' air-to-water heat pump. It’s a newly built house with two living units. The combined electricity consumption of both units is about 2200 kWh. Additionally, the pump consumes approximately 6600 kWh per year. Naively, I assumed my parents could invest around 25,000€ in a 9 kWp photovoltaic system and achieve a self-sufficient setup with very low electricity costs (about 30€ per month instead of 180€).
But that’s not the case. Firstly, a single-phase storage system is not an option because, due to the technology and grid regulations, the pump relies on the other two phases and will ALWAYS draw power from the grid. Even with a three-phase battery storage system, this problem would only be theoretically circumvented but not completely solved. Especially in winter, the pump runs at 80%-100% capacity while a photovoltaic system generates only about 30%-35% of its output in winter. In summer, the situation is almost exactly the opposite. This means we would underproduce in winter and overproduce in summer. On top of that, a three-phase battery system costs twice as much, and the number of manufacturers offering this option is very limited.
So, my question to the real experts: Should I just discard the idea of making the heat pump fully independent, or have I missed something?
I have gained a lot of knowledge in recent days through phone conversations with an engineer who is also a salesperson. However, I feel a bit uncomfortable bothering him further. He has already explained a lot to me. Also, information in written form is always better because you can look things up repeatedly and add to your knowledge. Therefore, it would be great if we could share our knowledge here together =)
I believe that savings on heating consumption alone will not yield significant results. In my opinion, this is only achievable with a 40+ standard, combined with corresponding savings in electricity consumption (about 35,000€ in subsidies for 2 residential units plus estimated annual electricity savings of 800-1,000€). This should make the whole project financially viable or at least break even.
Jochi is definitely right.
However, subsidies also need to be financed. Capital investment.
Either way, you have to pay for it if you build this way.
If you then break even or make a small profit: brilliant.
The rest currently – as of 2016 – depends on willingness, green expertise, enjoyment of the process, and having access to the necessary funds.
Honestly: zero interest rates or not, it’s difficult to offset the additional costs in a way that creates real financial enthusiasm. You can do optimistic calculations, but that remains just optimistic calculations.
Those building to KfW 40 or 40+ standards draw their motivation from somewhere else. I think that’s great – if you can and want to: go for it. A (nearly) self-sufficient house is a powerful, brilliant thing that would also bring me joy.
Energy efficiency regulations keep getting stricter anyway. I believe that by 2025 the region will have KfW 40+ or even more stringent standards as the norm.
Best regards
Thorsten
However, subsidies also need to be financed. Capital investment.
Either way, you have to pay for it if you build this way.
If you then break even or make a small profit: brilliant.
The rest currently – as of 2016 – depends on willingness, green expertise, enjoyment of the process, and having access to the necessary funds.
Honestly: zero interest rates or not, it’s difficult to offset the additional costs in a way that creates real financial enthusiasm. You can do optimistic calculations, but that remains just optimistic calculations.
Those building to KfW 40 or 40+ standards draw their motivation from somewhere else. I think that’s great – if you can and want to: go for it. A (nearly) self-sufficient house is a powerful, brilliant thing that would also bring me joy.
Energy efficiency regulations keep getting stricter anyway. I believe that by 2025 the region will have KfW 40+ or even more stringent standards as the norm.
Best regards
Thorsten
D
daniels8729 Mar 2016 11:22We hope to find out this week. It’s possible that the subsidies will break even at around zero. The lost living space due to the thicker bricks would need to be compensated for, which will probably depend on that.
daniels87 schrieb:
We hope to find out this week. It’s possible that the subsidies will end up roughly balanced. The lost living space due to the thicker brickwork will need to be compensated for, which will probably depend on that.Great, please be so kind and share any updates here then. Thank you.
jochi79 schrieb:
I will probably pursue the 40+ topic, or rather, the planning is currently strongly heading in that direction. Once I have more precise figures, we can definitely revisit the topic—I think it will be of interest to many in the future.Absolutely, it will be 100.0% interesting. It would be great if you could also report back at the appropriate time.
Thank you.
Similar topics