PhiTh
2016-05-20 09:33:23
- #1
Hello Thorsten,
Unfortunately, we are still in the planning phase, so I cannot give you data such as heat losses yet. However, the whole thing is based on the new building of my best friend, who has had his system running for about 4 years now.
As you already wrote, 7kwp is probably sufficient. The upper limit for me has always been 10kwp, as above that the Renewable Energy Act surcharge for self-consumption is due. The garage roof is large enough to accommodate 10kwp photovoltaics, which is why we will do it. Whether we need that much will show over time. It’s like with heating in general, there is no one right solution and it always turns out differently than the preliminary calculations say. Fortunately, we are able to rely on our gut feeling on many issues, and it tells us to "fill the roof" :)
The topic of storage is also a science in itself. We basically need a larger storage tank (calculated at about 4000L) because we heat with a corresponding log wood gasifier. Exactly because of the problem of heat loss, I did not want two storage tanks. Currently, we are planning with a 5000L storage tank. The tipping height is 3.1m. We are planning this in the construction as well. Certainly an "expensive" solution, but as I said, gut feeling :) The exact size of the solar system is not yet decided, as we are still struggling with the development plan due to the roof shape ;) I assume about 30-35m², although I currently prefer vacuum tubes. With the storage size, the solar system could also be significantly larger.
Regarding heat losses, I assume that the heated storage tank will supply heating and domestic hot water for about 4 days. This value is important to me. Since I heat with log wood and have to reload manually, every day more is a gain in comfort here. Economically, everyone advises me to have a smaller heater and to fire daily. These storage tanks are usually insulated with 10mm soft foam insulation, but I will consider something else here. I find that insufficient.
Unfortunately, we are still in the planning phase, so I cannot give you data such as heat losses yet. However, the whole thing is based on the new building of my best friend, who has had his system running for about 4 years now.
As you already wrote, 7kwp is probably sufficient. The upper limit for me has always been 10kwp, as above that the Renewable Energy Act surcharge for self-consumption is due. The garage roof is large enough to accommodate 10kwp photovoltaics, which is why we will do it. Whether we need that much will show over time. It’s like with heating in general, there is no one right solution and it always turns out differently than the preliminary calculations say. Fortunately, we are able to rely on our gut feeling on many issues, and it tells us to "fill the roof" :)
The topic of storage is also a science in itself. We basically need a larger storage tank (calculated at about 4000L) because we heat with a corresponding log wood gasifier. Exactly because of the problem of heat loss, I did not want two storage tanks. Currently, we are planning with a 5000L storage tank. The tipping height is 3.1m. We are planning this in the construction as well. Certainly an "expensive" solution, but as I said, gut feeling :) The exact size of the solar system is not yet decided, as we are still struggling with the development plan due to the roof shape ;) I assume about 30-35m², although I currently prefer vacuum tubes. With the storage size, the solar system could also be significantly larger.
Regarding heat losses, I assume that the heated storage tank will supply heating and domestic hot water for about 4 days. This value is important to me. Since I heat with log wood and have to reload manually, every day more is a gain in comfort here. Economically, everyone advises me to have a smaller heater and to fire daily. These storage tanks are usually insulated with 10mm soft foam insulation, but I will consider something else here. I find that insufficient.