Hello, we are currently planning our new build. We are choosing a gas heating system with solar support for domestic hot water. Would you also consider solar support for space heating?
Would you also connect a hydronic fireplace?
Would you also connect a hydronic fireplace?
We are a household of two people, living in a single-family house with 135 sqm (1453 sq ft) of usable floor space.
We use a gas boiler with solar support for domestic hot water heating. Two Logasol SKN 4.0 collectors are installed, with a total area of 4.8 sqm (52 sq ft).
I can easily calculate the daily costs for domestic hot water heating when the collector provides no energy:
0.4 cubic meters of gas, equivalent to about 4.2 kWh or $0.30 per day.
This is the maximum amount the collector can save for us, minus the electricity costs for the circulation pump of the solar fluid, which is about 5 cents. That leaves 25 cents per day in savings, generously estimated over 200 days per year. This results in $50 per year.
The investment costs can never be recovered over the system’s lifetime.
A vacuum tube flat-plate collector would have generated significantly more yield, but it is considerably more expensive to purchase.
I also believe that supporting the heating circuit only has a minor effect and is not cost-effective; it definitely requires a vacuum tube flat-plate collector of appropriate size. Since every percent counts here, pure south-facing orientation is important. Due to my east-facing orientation, I lose about another 10%, so it was not even considered to install or invest in.
Regards,
Thorsten
We use a gas boiler with solar support for domestic hot water heating. Two Logasol SKN 4.0 collectors are installed, with a total area of 4.8 sqm (52 sq ft).
I can easily calculate the daily costs for domestic hot water heating when the collector provides no energy:
0.4 cubic meters of gas, equivalent to about 4.2 kWh or $0.30 per day.
This is the maximum amount the collector can save for us, minus the electricity costs for the circulation pump of the solar fluid, which is about 5 cents. That leaves 25 cents per day in savings, generously estimated over 200 days per year. This results in $50 per year.
The investment costs can never be recovered over the system’s lifetime.
A vacuum tube flat-plate collector would have generated significantly more yield, but it is considerably more expensive to purchase.
I also believe that supporting the heating circuit only has a minor effect and is not cost-effective; it definitely requires a vacuum tube flat-plate collector of appropriate size. Since every percent counts here, pure south-facing orientation is important. Due to my east-facing orientation, I lose about another 10%, so it was not even considered to install or invest in.
Regards,
Thorsten
S
Sebastian7920 Nov 2015 12:26Great, finally some simple, clear numbers revealing the harsh reality of solar nonsense.
Hi,
I can’t really judge whether the numbers from T21150 are accurate, but the magnitude should be roughly correct.
We have a similarly sized house, gas heating plus 5 sqm (54 sqft) of solar thermal, and use about 8500 kWh of gas per year. Our heating system roughly tells us how much solar support it collects. It never exceeds 10 kWh per day, even in summer. Simply because not much more energy is used for showers and such. So let’s generously estimate 1000 kWh for the whole year. That’s about 50 €/year.
Sebastian is right, this is all complete nonsense. Especially considering that producing 1 kg of glass requires about 1300 kWh of energy. I honestly have no idea how much glass is used here, but it will definitely take several years before these devices recover even the energy used for their production—if they manage to at all.
But since these things are now often manufactured somewhere in the Far East, that’s of course *bad* CO2 from the *bad* Chinese, while we here are the great good guys saving so much CO2. And since the *bad* CO2 from the *bad* Chinese certainly won’t cross the border, we can all pat ourselves on the back here for all the great things we’re doing for the environment.
Lord, please send some sense from above!
Back to the topic:
@Sebastian
The solar system’s real purpose isn’t really to provide heating but just to get approval for the gas condensing boiler.
By far the cheapest heating is a gas boiler without solar or anything else. Unfortunately, you can no longer get approval for that in this country, which is by no means short of nonsense. So the only alternatives are gas heating with solar (4–5 sqm (43–54 sqft) for domestic hot water support), which is still cheaper than a heat pump, or from next year a gas boiler with solar heating support (10–15 sqm (108–161 sqft)). The latter probably won’t be much different in cost compared to a good heat pump with indoor installation.
From next year, you won’t have the option of “gas heating combined with solar domestic hot water support” anymore, or only with extremely extensive insulation.
Best regards,
Andreas
I can’t really judge whether the numbers from T21150 are accurate, but the magnitude should be roughly correct.
We have a similarly sized house, gas heating plus 5 sqm (54 sqft) of solar thermal, and use about 8500 kWh of gas per year. Our heating system roughly tells us how much solar support it collects. It never exceeds 10 kWh per day, even in summer. Simply because not much more energy is used for showers and such. So let’s generously estimate 1000 kWh for the whole year. That’s about 50 €/year.
Sebastian is right, this is all complete nonsense. Especially considering that producing 1 kg of glass requires about 1300 kWh of energy. I honestly have no idea how much glass is used here, but it will definitely take several years before these devices recover even the energy used for their production—if they manage to at all.
But since these things are now often manufactured somewhere in the Far East, that’s of course *bad* CO2 from the *bad* Chinese, while we here are the great good guys saving so much CO2. And since the *bad* CO2 from the *bad* Chinese certainly won’t cross the border, we can all pat ourselves on the back here for all the great things we’re doing for the environment.
Lord, please send some sense from above!
Back to the topic:
@Sebastian
The solar system’s real purpose isn’t really to provide heating but just to get approval for the gas condensing boiler.
By far the cheapest heating is a gas boiler without solar or anything else. Unfortunately, you can no longer get approval for that in this country, which is by no means short of nonsense. So the only alternatives are gas heating with solar (4–5 sqm (43–54 sqft) for domestic hot water support), which is still cheaper than a heat pump, or from next year a gas boiler with solar heating support (10–15 sqm (108–161 sqft)). The latter probably won’t be much different in cost compared to a good heat pump with indoor installation.
From next year, you won’t have the option of “gas heating combined with solar domestic hot water support” anymore, or only with extremely extensive insulation.
Best regards,
Andreas
S
Sebastian7920 Nov 2015 14:48And then at most a gas condensing boiler with zeolite or huge solar panels?
What nonsense...
What nonsense...
Correct, Sebastian.
More or less: economic nonsense.
Apart from passive houses, in a modern building nowadays, depending on the volume/size, there is still a savings potential of about 50-80 euros per month until it reaches zero. But only with exponentially increasing investment costs.
Capital costs money just like heating does.
If you already have the capital and want to experiment: no problem. I would do that too in that case, experiment. Unfortunately, I am not wealthy. Just an ordinary person.........
Poorly insulated older buildings – I often see listings here in the newspaper showing 200–450 kWh/m²/year (21–42 kBtu/ft²/year), which have more potential than purely expensive upgrades to already efficient low-energy houses. The comparisons are often based on primary energy anyway, which doesn’t provide information about actual consumption and local costs for the builder.
More or less: economic nonsense.
Apart from passive houses, in a modern building nowadays, depending on the volume/size, there is still a savings potential of about 50-80 euros per month until it reaches zero. But only with exponentially increasing investment costs.
Capital costs money just like heating does.
If you already have the capital and want to experiment: no problem. I would do that too in that case, experiment. Unfortunately, I am not wealthy. Just an ordinary person.........
Poorly insulated older buildings – I often see listings here in the newspaper showing 200–450 kWh/m²/year (21–42 kBtu/ft²/year), which have more potential than purely expensive upgrades to already efficient low-energy houses. The comparisons are often based on primary energy anyway, which doesn’t provide information about actual consumption and local costs for the builder.
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