We have a small solar thermal system on the roof. This was mandatory because we have a gas heating system (heating station with storage tank from the company Wolf). We wanted to finally find out how effective our system actually is. At first, we thought we were just not able to find the data on the display. After a lot of back and forth with the heating company, it turned out that our system does not have a heat meter. "The system only saves about 5% anyway. And we only installed it because it’s legally required," was the response. I’m quite surprised by this... This is the first time I’ve heard that. We paid a lot of money for it but have no way to verify what the system actually delivers. Is that common?
How is it for you? What kind of savings do your solar collectors provide? Can you read out your heat output?
Best regards,
Steffi33
How is it for you? What kind of savings do your solar collectors provide? Can you read out your heat output?
Best regards,
Steffi33
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Steffen8031 May 2018 15:06wrobel schrieb:
Hello again,
I think this approach is indeed "goal-oriented," although everyone has different objectives. This solution likely involves a slight loss of comfort. However, the advantage is that I can monitor the performance of my solar system and prevent it from competing with the heat generator. This can also be moderated by adjusting the target temperature and the heating boost time window to avoid too much discomfort.
OlliI believe you misunderstood me. Hot water = 0 degrees means no hot water at the tap anymore... how is that supposed to be goal-oriented?
Why make it so complicated? Can't you set a hot water program on your heating system (with my gas boiler, this is possible)? For example, set specific times during which the heating should reach the desired hot water temperature.
I only allow my gas boiler to heat between 5 PM and 8 PM during the summer. As a result, on any reasonably sunny day, the storage tank is warm by then thanks to the solar system --> gas consumption is 0.0 cubic meters.
I only allow my gas boiler to heat between 5 PM and 8 PM during the summer. As a result, on any reasonably sunny day, the storage tank is warm by then thanks to the solar system --> gas consumption is 0.0 cubic meters.
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Steffen801 Jun 2018 14:10This creates two problems: 1. If there is no sun for a longer period, you will probably have cold water. 2. If there are only a few days without sun, you will heat up again every day. I only allow my boiler to reheat when the buffer tank drops below 40°C (104°F), regardless of the time of day. This way, I can manage to go a whole week without any sun at all with zero gas consumption 🙂
For me, there are absolutely no problems. Cold water never occurs. If, in rare cases, solar radiation is insufficient, the warm water from the previous evening easily lasts until the afternoon of the next day....
However, this has NEVER happened so far, since I have vacuum tube collectors and not flat plate collectors on the roof. Consequently, even diffuse light is sufficient thanks to the parabolic mirrors.
And why would I need additional heating? Just like you, I can simply lower the target temperature for the gas heating system, for example to 40°C (104°F).
However, this has NEVER happened so far, since I have vacuum tube collectors and not flat plate collectors on the roof. Consequently, even diffuse light is sufficient thanks to the parabolic mirrors.
And why would I need additional heating? Just like you, I can simply lower the target temperature for the gas heating system, for example to 40°C (104°F).
Well, every manufacturer has their own approach.
For example, my system has two parameters: hot water (set to 45°C [113°F]) and solar hot water (set to 70°C [158°F]). Additionally, the system can automatically distinguish between summer and winter thanks to a built-in timer, so it only heats during summer if there hasn’t been sunlight for an extended period.
As long as the solar thermal system manages to heat the storage tank to at least 46°C (115°F), the gas valve remains closed.
P.S. with 5 square meters (54 square feet) of flat plate collectors on a 45° south-facing roof.
For example, my system has two parameters: hot water (set to 45°C [113°F]) and solar hot water (set to 70°C [158°F]). Additionally, the system can automatically distinguish between summer and winter thanks to a built-in timer, so it only heats during summer if there hasn’t been sunlight for an extended period.
As long as the solar thermal system manages to heat the storage tank to at least 46°C (115°F), the gas valve remains closed.
P.S. with 5 square meters (54 square feet) of flat plate collectors on a 45° south-facing roof.
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