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 =)
Building 40+
What information do you need? We are paying approximately €227,000 for 145 m² (1,560 sq ft) over 1.5 floors with a knee wall of 140 cm (55 inches). We have excluded interior finishing materials worth €18,000 and labor for these materials worth €24,000. We will handle these ourselves or have them done more cheaply. The photovoltaic system, which costs €15,000, is also not provided by the builder, as they offer it for €20,000 and it is not the one we want.
What information do you need? We are paying approximately €227,000 for 145 m² (1,560 sq ft) over 1.5 floors with a knee wall of 140 cm (55 inches). We have excluded interior finishing materials worth €18,000 and labor for these materials worth €24,000. We will handle these ourselves or have them done more cheaply. The photovoltaic system, which costs €15,000, is also not provided by the builder, as they offer it for €20,000 and it is not the one we want.
jochi79 schrieb:
@Inotsara
Could you please share the technical details of the installed equipment (mechanical ventilation with heat recovery, photovoltaic system, battery, etc.)?We chose the photovoltaic system ourselves; we decided on the Tesla Powerwall with 6.3 kWh (6.3 kWh) storage capacity and a 5.88 kWp (5.88 kWp) roof-mounted solar array. The air-to-water heat pump comes from our developer and is a Viessmann unit with a ventilation system. I believe it is this model:Viessmann Split Air/Water Heat Pump package Vitocal 200-S AWB-AC
We didn’t have many options except for choosing between an external or internal installation.
As soon as the installation takes place and I have more technical details, I will publish them on our blog. There, I document every step and progress very thoroughly.
Sascha aus H29 Apr 2016 14:48Inotsara schrieb:
The selected material for interior finishing was 18,000 and the services for it 24,000. We will do that ourselves or have it done more cheaply. Could you please explain what is included in the interior finishing?
T21150 schrieb:
Just: If I had known back then that KFW70 would be discontinued and become the standard in 2016, I would very likely have built KFW55 solely because of the market/resale value.Hello Thorsten,
I just came across this post.
Do you really think anyone will care in 20 to 30 years which energy standard the house was built to? I believe this question won’t be asked (as is mostly the case today) and won’t significantly affect the resale price.
Let’s take a look at the current situation in the (used) property market. In areas with medium to high demand, well-maintained used homes usually sell without any problem. Anyone buying such a property knows they need to budget a certain amount for renovation or refurbishment (primarily for the heating system, which will no longer meet current standards). In these discussions, the only question that typically comes up is the type of heating (oil or gas).
In my opinion, it will be similar in 20 to 30 years. Maybe the question will be about gas or heat pump systems. But since today’s gas heaters and heat pumps will no longer meet the technical standards of the future, a replacement will be planned by the buyer from the outset.
And honestly — if I show an energy certificate 30 years from now, most buyers probably won’t know how to interpret it or understand its relevance. Not to mention that they might not even know which energy regulation applied in the year the house was built or how to translate it into today’s standards.
T
toxicmolotof9 May 2016 16:12In the end, the question in X years will be: How much do I have to pay monthly for heating energy?
It doesn’t matter whether it’s 100 euros for electricity or 100 euros for gas, wood, or whatever.
It doesn’t matter whether it’s 100 euros for electricity or 100 euros for gas, wood, or whatever.
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