Hello,
this is my first post in this forum... Hello everyone.
My partner and I have just started building a house. The construction is being done by a contractor, except for the electrical work, which I am doing myself.
I have a few questions.
We insulated the foundation slab with 10 cm (4 inches) of insulation. The exterior walls will be insulated with cavity insulation from Rockwool: one 60 mm (2.4 inches) board and another 80 mm (3 inches) board staggered on top. The roof will be insulated with 240 mm (9.5 inches). The windows are triple-glazed with a U-value of 0.8.
We will have a standard gas heating system installed, with radiators in the rooms.
Now, according to the new regulations, we have to use renewable energy. We have looked into the Vaillant auro VSC 196 20 and think Vaillant is very good. The system includes a 150-liter (40-gallon) stratified storage tank for two solar collectors that come in a set.
Our house is 120 m² (1,292 ft²) and two people will live in it.
My questions are:
Is this heating system with the solar collectors sufficient?
Do I need a residential ventilation system with the type of insulation we have?
If yes, can I pre-install the ductwork now and add the rest later?
Budget is, of course, an important factor.
I would appreciate any advice.
Best regards,
Stefan
this is my first post in this forum... Hello everyone.
My partner and I have just started building a house. The construction is being done by a contractor, except for the electrical work, which I am doing myself.
I have a few questions.
We insulated the foundation slab with 10 cm (4 inches) of insulation. The exterior walls will be insulated with cavity insulation from Rockwool: one 60 mm (2.4 inches) board and another 80 mm (3 inches) board staggered on top. The roof will be insulated with 240 mm (9.5 inches). The windows are triple-glazed with a U-value of 0.8.
We will have a standard gas heating system installed, with radiators in the rooms.
Now, according to the new regulations, we have to use renewable energy. We have looked into the Vaillant auro VSC 196 20 and think Vaillant is very good. The system includes a 150-liter (40-gallon) stratified storage tank for two solar collectors that come in a set.
Our house is 120 m² (1,292 ft²) and two people will live in it.
My questions are:
Is this heating system with the solar collectors sufficient?
Do I need a residential ventilation system with the type of insulation we have?
If yes, can I pre-install the ductwork now and add the rest later?
Budget is, of course, an important factor.
I would appreciate any advice.
Best regards,
Stefan
Hello bangolo,
Why is that necessary for a house (Energy Saving Ordinance 2007) that already ventilates too much? The system can’t prevent that anyway, can it?
What do geothermal collectors have to do with building component activation? They are located outside the building structure, aren’t they? Or are you referring to cooling?
Hybrid collectors are not sophisticated but inefficient; combining both subsystems (thermal and photovoltaic) actually reduces the efficiency of each.
I consider the information on the homepage "Heating Engineering Office – Heating" to be purely marketing.
They imply that the heating load of a building does not matter, which is incorrect.
Quote from the slogan:
"A particularly energy-saving construction method for the building is not required; only the valid thermal insulation regulations must be met."
It is also suggested that the collectors heat the buffer tank for the heating system, which is not possible in our climate zones; currently, the yield is about 14%.
Quote from the slogan:
"The solar collectors primarily charge and supply the buffer tank with heat."
The focus should not be on the heating system but on thermal insulation. If you reverse this principle, you would always end up with an oversized heating system. Neither the investment nor the operational and maintenance costs would be necessary.
Best regards
A controlled mechanical ventilation system should definitely be installed.
Why is that necessary for a house (Energy Saving Ordinance 2007) that already ventilates too much? The system can’t prevent that anyway, can it?
What do geothermal collectors have to do with building component activation? They are located outside the building structure, aren’t they? Or are you referring to cooling?
Hybrid collectors are not sophisticated but inefficient; combining both subsystems (thermal and photovoltaic) actually reduces the efficiency of each.
I consider the information on the homepage "Heating Engineering Office – Heating" to be purely marketing.
They imply that the heating load of a building does not matter, which is incorrect.
Quote from the slogan:
"A particularly energy-saving construction method for the building is not required; only the valid thermal insulation regulations must be met."
It is also suggested that the collectors heat the buffer tank for the heating system, which is not possible in our climate zones; currently, the yield is about 14%.
Quote from the slogan:
"The solar collectors primarily charge and supply the buffer tank with heat."
The focus should not be on the heating system but on thermal insulation. If you reverse this principle, you would always end up with an oversized heating system. Neither the investment nor the operational and maintenance costs would be necessary.
Best regards
Hello Parcus,
I replied to spacecowboy’s post.
It doesn’t mention the Energy Saving Ordinance 2007, which is why I wrote that I would use a controlled mechanical ventilation system.
Maybe you didn’t read the article carefully. The heat collected in summer by the solar system is stored in ceilings, walls, and foundations. If that heat storage is not sufficient, additional ground collectors are installed, and the soil is basically used as a long-term storage. In winter, this stored heat is then retrieved via a heat pump. Of course, you can also switch the heat pump to use the stored heat for cooling in the summer. There is a similar system by Consolar (I’ll skip the link) which uses an ice storage installed in the ground.
The efficiency is not reduced, but rather the available surface area. Naturally, you can also install photovoltaic modules in addition to the thermal solar collectors, as the article about the immosolar system explains.
For one, nothing is sold on the site. It provides information about new technologies and products, mostly from heating engineering. What’s the problem?
It clearly states that the valid thermal protection regulation must be followed. Where does it say the heating load doesn’t matter?
Well-designed solar systems combined with an appropriate building and heating technology can achieve up to 30% coverage. But that’s not the point here. The sentence merely means that first the buffer tank is charged and then the activated building components and/or the ground storage are used. This approach makes sense because you can use the high temperatures delivered by the solar system efficiently.
I don’t understand. The sentence is perfectly clear: the better the insulation, the smaller the heating system can be. Otherwise, passive houses or plus-energy houses would make no sense.
I’m a bit surprised; as a specialist in ecological building, you should like such a system. 100% solar energy, year-round temperatures for the heat pump from 15 to 20 degrees Celsius (59 to 68 degrees Fahrenheit) – of course, this is a high-end system that is certainly not cheap.
I replied to spacecowboy’s post.
We received from the building contractor a "Certificate for energy-saving thermal protection and energy-saving system technology for buildings according to the Energy Saving Ordinance 2009."
It doesn’t mention the Energy Saving Ordinance 2007, which is why I wrote that I would use a controlled mechanical ventilation system.
What do geothermal collectors have to do with building component activation? They are located outside the building, or are you referring to cooling?
Maybe you didn’t read the article carefully. The heat collected in summer by the solar system is stored in ceilings, walls, and foundations. If that heat storage is not sufficient, additional ground collectors are installed, and the soil is basically used as a long-term storage. In winter, this stored heat is then retrieved via a heat pump. Of course, you can also switch the heat pump to use the stored heat for cooling in the summer. There is a similar system by Consolar (I’ll skip the link) which uses an ice storage installed in the ground.
Hybrid collectors are not premium quality but inefficient; the combination lowers the efficiency of both subsystems (thermal and photovoltaic).
The efficiency is not reduced, but rather the available surface area. Naturally, you can also install photovoltaic modules in addition to the thermal solar collectors, as the article about the immosolar system explains.
I consider the information on the webpage "Heating Engineering Office – Heating" to be pure marketing.
For one, nothing is sold on the site. It provides information about new technologies and products, mostly from heating engineering. What’s the problem?
This suggests that the heating load of a building does not matter, which is incorrect.
Quote from the slogan:
A particularly energy-efficient construction of the building is not required; it only needs to comply with the valid thermal protection regulation.
It clearly states that the valid thermal protection regulation must be followed. Where does it say the heating load doesn’t matter?
It is further suggested that the collectors heat the buffer tank for the heating system, which is not possible in our latitudes; current yields are about 14%.
Quote from the slogan:
The buffer tank is primarily charged and heated by the solar collectors.
Well-designed solar systems combined with an appropriate building and heating technology can achieve up to 30% coverage. But that’s not the point here. The sentence merely means that first the buffer tank is charged and then the activated building components and/or the ground storage are used. This approach makes sense because you can use the high temperatures delivered by the solar system efficiently.
Not the heating system but the thermal insulation is the focus.
If you reverse this principle, you would always buy a much too large heating system. Neither the investment nor the operating and maintenance costs would be necessary.
I don’t understand. The sentence is perfectly clear: the better the insulation, the smaller the heating system can be. Otherwise, passive houses or plus-energy houses would make no sense.
I’m a bit surprised; as a specialist in ecological building, you should like such a system. 100% solar energy, year-round temperatures for the heat pump from 15 to 20 degrees Celsius (59 to 68 degrees Fahrenheit) – of course, this is a high-end system that is certainly not cheap.
Hello bangolo,
I am questioning the use of an earth coil in conjunction with thermal activation of building components, as the earth coil is not actually a structural element. With thermal activation, we generally agree that it involves existing ceilings and walls with small temperature differences to the room, or insulated thermal storage elements with a higher temperature gradient to the room, which release heat in a controlled manner. The RUD. OTTO MEYER ENVIRONMENT FOUNDATION’s "Thermal Activation of Building Components" offers a good overview of this.
I do not consider an external earth coil suitable here, as it cannot store heat for long against the surrounding ground temperature. Furthermore, heat release cannot be controlled like it is with an insulated thermal storage element, especially given the high temperature difference to the room. Earthships are a different matter, where the earth itself acts as a storage medium for the wall.
Perhaps we just misunderstood each other.
Regarding hybrid collectors, the Association of Solar Manufacturers at this year’s Renewable Energy Trade Fair in Gelsenkirchen expressed the opinion that this technology is currently not efficient. The more cost-effective solar thermal systems influence photovoltaic module performance so much through their temperature that these modules no longer generate returns after the feed-in tariff. However, these systems come with higher investment costs.
Quote from the homepage
However, the heating load results from this, independent of the energy saving ordinance, which only regulates the minimum requirements.
Optimally designed solar systems combined with a suitable building and appropriate heating technology achieve up to 30% coverage.
I am always open to learning; please provide a link here.
Best regards
I am questioning the use of an earth coil in conjunction with thermal activation of building components, as the earth coil is not actually a structural element. With thermal activation, we generally agree that it involves existing ceilings and walls with small temperature differences to the room, or insulated thermal storage elements with a higher temperature gradient to the room, which release heat in a controlled manner. The RUD. OTTO MEYER ENVIRONMENT FOUNDATION’s "Thermal Activation of Building Components" offers a good overview of this.
I do not consider an external earth coil suitable here, as it cannot store heat for long against the surrounding ground temperature. Furthermore, heat release cannot be controlled like it is with an insulated thermal storage element, especially given the high temperature difference to the room. Earthships are a different matter, where the earth itself acts as a storage medium for the wall.
Perhaps we just misunderstood each other.
Regarding hybrid collectors, the Association of Solar Manufacturers at this year’s Renewable Energy Trade Fair in Gelsenkirchen expressed the opinion that this technology is currently not efficient. The more cost-effective solar thermal systems influence photovoltaic module performance so much through their temperature that these modules no longer generate returns after the feed-in tariff. However, these systems come with higher investment costs.
It clearly says that the applicable thermal insulation regulations must be met; where does it say that the heating load does not matter?
Quote from the homepage
An especially energy-saving construction of the building is not required
However, the heating load results from this, independent of the energy saving ordinance, which only regulates the minimum requirements.
Optimally designed solar systems combined with a suitable building and appropriate heating technology achieve up to 30% coverage.
I am always open to learning; please provide a link here.
Best regards
Hello Parcus,
I think we are really talking past each other here. The system in question is about storing heat generated by the solar system in summer for use in winter. The term "thermal activation of building components" isn’t exactly correct here; let’s call it long-term solar storage. That’s why it doesn’t matter if the ground loses some heat—the heat is there anyway, generated by the solar system. So, where should it go? Possibly into the ground via a ground collector, and also into the building components.
By the way, I see a much bigger problem with that—especially with ceilings or walls—you can’t heat them up infinitely in summer, otherwise you might end up having to cool the rooms forcibly. That is probably why the manufacturer mainly uses foundations and walls of non-living spaces, ideally basements or similar, as heat storage. Again, this creates a problem because you are heating the basement.
Now it gets even trickier. Various scientific studies actually suggest that solar long-term storage does not work well in our latitudes, mainly due to heat losses. Those studies usually refer to buffer storage—I agree with that. But with this system configuration, the energy collected in summer is used in winter with a heat pump.
Please don’t take sentences out of context.
This sentence was actually one reason why I started looking more closely at this issue. Unfortunately, my house does not comply with any thermal insulation regulation—it dates from 1898 and has sandstone exterior walls, not a facade, just 80 cm (31 inches) thick natural sandstone walls. Additionally, the house still has windows with decorative moldings. Naturally, I have been looking for solutions on how to save energy. Only the Immosolar people waved me off because I need very high flow temperatures. Currently, I have a low-temperature gas heating system at 75/55 (°C) (167/131 °F) with panel radiators. I also have enough roof area, all nicely facing southwest.
I can’t give you a link to such a heating system because you would need a system that has been monitored with measurements over several years to have real data. Otherwise, I can only rely on manufacturer information.
One thing is clear: especially solar systems and heat pumps must be calculated very precisely before you can ultimately say whether they are worthwhile.
I think we are really talking past each other here. The system in question is about storing heat generated by the solar system in summer for use in winter. The term "thermal activation of building components" isn’t exactly correct here; let’s call it long-term solar storage. That’s why it doesn’t matter if the ground loses some heat—the heat is there anyway, generated by the solar system. So, where should it go? Possibly into the ground via a ground collector, and also into the building components.
By the way, I see a much bigger problem with that—especially with ceilings or walls—you can’t heat them up infinitely in summer, otherwise you might end up having to cool the rooms forcibly. That is probably why the manufacturer mainly uses foundations and walls of non-living spaces, ideally basements or similar, as heat storage. Again, this creates a problem because you are heating the basement.
Now it gets even trickier. Various scientific studies actually suggest that solar long-term storage does not work well in our latitudes, mainly due to heat losses. Those studies usually refer to buffer storage—I agree with that. But with this system configuration, the energy collected in summer is used in winter with a heat pump.
Please don’t take sentences out of context.
An especially energy-saving building design is not required; it only has to comply with the current thermal insulation regulations.
This sentence was actually one reason why I started looking more closely at this issue. Unfortunately, my house does not comply with any thermal insulation regulation—it dates from 1898 and has sandstone exterior walls, not a facade, just 80 cm (31 inches) thick natural sandstone walls. Additionally, the house still has windows with decorative moldings. Naturally, I have been looking for solutions on how to save energy. Only the Immosolar people waved me off because I need very high flow temperatures. Currently, I have a low-temperature gas heating system at 75/55 (°C) (167/131 °F) with panel radiators. I also have enough roof area, all nicely facing southwest.
I can’t give you a link to such a heating system because you would need a system that has been monitored with measurements over several years to have real data. Otherwise, I can only rely on manufacturer information.
One thing is clear: especially solar systems and heat pumps must be calculated very precisely before you can ultimately say whether they are worthwhile.
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