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 =)
RobsonMKK schrieb:
I think you still haven’t understood that for most people it’s not about making big profits. It’s about using as much self-generated electricity as possible and having a certain level of independence if needed. Yes, I did say that if you see it as a technical hobby and want to spend money on it, that’s fine. Not everything has to be economical.
Degree of autonomy is a nice euphemism. You’re either fully independent or you’re not. Whether you draw more or less electricity from the grid can also be achieved by energy-efficient appliances, watching less TV, LEDs, and so on.
Just the fact that a photovoltaic system usually generates single-phase power, while the electrical loads run across all three phases, generally prevents a larger portion of the electricity from being actually self-consumed. The three-phase summing meter then presents an illusion that, in a real “emergency,” wouldn’t be possible. This is purely a mathematical/legal independence.
Here again is my last paragraph:
Grym schrieb:
But if you see it as a technical hobby, then you buy the system for 5,000-6,000 EUR, save about 2,000 EUR over 10-20 years, and treat the remaining 3,500 EUR as a hobby expense—and that’s it. No one’s stopping anyone. It’s a nice hobby, really.Similar topics