ᐅ Heating with gas, ventilation through a mechanical ventilation system, and cooling with air conditioning?
Created on: 15 Jul 2018 19:03
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EinMarcHello,
after a long search and effort, we finally acquired a plot of land about 25km north of Stuttgart, and we are now slowly starting the building planning. Right now, I am thinking about heating and cooling options.
In this established residential area, natural gas is available right at the 5.5 ares (0.14 acres) large plot. As far as I know, there are no requirements besides the energy saving regulation. The house will have about 360m² (3,875 sq ft) gross floor area, of which 240m² (2,583 sq ft) gross will be heated (cold basement).
Since I am somewhat skeptical about heat pumps running continuously, we would prefer to heat with gas, especially since it is already available on site. I have also read often that this is usually more cost-effective at this size. Of course, exact calculations will have to be made once the plans are more developed.
I have often read that the required percentage of renewable energy might also be provided by a mechanical ventilation system with heat recovery.
I have favored a controlled mechanical ventilation system anyway due to severe hay fever and poor natural ventilation habits, so this option would be the final push to decide in favor of that investment.
Furthermore, like in our current home, we would also like to operate an air conditioning system. It is only used on a few days when it is extremely humid and/or hot, but we want to be able to rely on it in the new home as well.
This raises my question:
Is there such a solution available as a “package”? Or at least an option combining air conditioning with the mechanical ventilation system?
How recommendable or maintenance-intensive is such a system? I imagine it could be quite challenging if a lot of cold air has to flow through long ducts inside the house. Especially regarding condensation and the resulting buildup of dust and other breeding grounds inside the ducts. Or is this not an issue?
Basically, only the living room and bedroom would need cooling, which could be done with a dual-split system with indoor units in the respective rooms. But how does that work together with the mechanical ventilation? Would you have to turn off the ventilation system, otherwise all the cold air would be exchanged, right?
Can the heat recovery system also recover cold air? That is, does the heat exchanger work in the opposite direction as well? If yes, what happens to the inevitable condensation that occurs in that case?
Thank you very much in advance for your time and best regards,
Marc
after a long search and effort, we finally acquired a plot of land about 25km north of Stuttgart, and we are now slowly starting the building planning. Right now, I am thinking about heating and cooling options.
In this established residential area, natural gas is available right at the 5.5 ares (0.14 acres) large plot. As far as I know, there are no requirements besides the energy saving regulation. The house will have about 360m² (3,875 sq ft) gross floor area, of which 240m² (2,583 sq ft) gross will be heated (cold basement).
Since I am somewhat skeptical about heat pumps running continuously, we would prefer to heat with gas, especially since it is already available on site. I have also read often that this is usually more cost-effective at this size. Of course, exact calculations will have to be made once the plans are more developed.
I have often read that the required percentage of renewable energy might also be provided by a mechanical ventilation system with heat recovery.
I have favored a controlled mechanical ventilation system anyway due to severe hay fever and poor natural ventilation habits, so this option would be the final push to decide in favor of that investment.
Furthermore, like in our current home, we would also like to operate an air conditioning system. It is only used on a few days when it is extremely humid and/or hot, but we want to be able to rely on it in the new home as well.
This raises my question:
Is there such a solution available as a “package”? Or at least an option combining air conditioning with the mechanical ventilation system?
How recommendable or maintenance-intensive is such a system? I imagine it could be quite challenging if a lot of cold air has to flow through long ducts inside the house. Especially regarding condensation and the resulting buildup of dust and other breeding grounds inside the ducts. Or is this not an issue?
Basically, only the living room and bedroom would need cooling, which could be done with a dual-split system with indoor units in the respective rooms. But how does that work together with the mechanical ventilation? Would you have to turn off the ventilation system, otherwise all the cold air would be exchanged, right?
Can the heat recovery system also recover cold air? That is, does the heat exchanger work in the opposite direction as well? If yes, what happens to the inevitable condensation that occurs in that case?
Thank you very much in advance for your time and best regards,
Marc
EinMarc schrieb:
Hello,
[...]
Can heat recovery ventilators also recover cold air? In other words, does the heat exchanger work in the opposite direction as well? If so, what happens to the condensate that inevitably forms there?
MarcYes. The condensate behaves the same way as in winter. It drains into the condensate drain.
By the way, a heat pump can also provide cooling, either actively or passively depending on the model, often via the underfloor heating system.
Don’t make any decisions upfront. Calculate all the costs for the house with different insulation levels, including the appropriate heating system. An uninsulated basement is really outdated. You will then need insulation in the ceiling between floors and a thick, airtight door to the basement.
I have tested this exact setup.
Gas including heating system + mechanical ventilation with heat recovery + air conditioning.
You can forget the idea of using mechanical ventilation to cool or transport cold air. The airflow volume is simply too low. Ventilation is just ventilation.
Mechanical ventilation alone is rarely sufficient as an alternative solution. In that case, everything else must be extremely well coordinated. However, with additional insulation, the energy saving regulations are usually met.
Gas including heating system + mechanical ventilation with heat recovery + air conditioning.
You can forget the idea of using mechanical ventilation to cool or transport cold air. The airflow volume is simply too low. Ventilation is just ventilation.
Mechanical ventilation alone is rarely sufficient as an alternative solution. In that case, everything else must be extremely well coordinated. However, with additional insulation, the energy saving regulations are usually met.
Hello both,
Thank you very much for the quick replies.
So, the basement would not be uninsulated, just unheated. This option results from two reasons:
a) There will be very high point loads placed and frequently moved in the basement. This does not work well with underfloor heating, especially if a heat pump were to be installed, and
b) based on previous experience, heating down there does not seem necessary. In our current house, despite regular use of the basement (hobby workshop), I have never turned on the heater since 2004. It simply was never necessary.
It only needs to be dry down there, not warm. But that also depends a bit on the heating choice. With gas heating, you can avoid underfloor heating, so a manageable investment in a few radiators and pipes would not be a problem.
But underfloor heating with large point loads is quite complicated to implement, isn’t it? We’re talking about 2 tons on just a few cm² (square inches), which heating coils probably don’t like.
It’s good to know there is a condensate drain at the heat exchanger, thank you.
@Mycraft
And so far no problems or required cleaning of the controlled mechanical ventilation ducts due to condensate buildup there? Which model/manufacturer did you install? Filters at the exhaust vents in the rooms? In general, it would be interesting to hear about proven manufacturers and models for the entire project—your heating system, solar thermal elements, ventilation, and air conditioning. Feel free to share via private message, thanks!
@fragg
I would prefer not to use underfloor heating for cooling. On one hand, it doesn’t seem physically reasonable to cover cooling via the lowest surface in the room without ventilation above it; on the other hand, I don’t want the floor to be the coldest point. Your feet would get frozen^^ Better to have a full air conditioning system. That also provides the benefit of draining warm and humid air, which is what makes the climate change feel quick and noticeable—not just the cooler air. With AC, at least you know exactly where the condensate will occur. I definitely don’t want that on the floor.
Thank you very much for the quick replies.
So, the basement would not be uninsulated, just unheated. This option results from two reasons:
a) There will be very high point loads placed and frequently moved in the basement. This does not work well with underfloor heating, especially if a heat pump were to be installed, and
b) based on previous experience, heating down there does not seem necessary. In our current house, despite regular use of the basement (hobby workshop), I have never turned on the heater since 2004. It simply was never necessary.
It only needs to be dry down there, not warm. But that also depends a bit on the heating choice. With gas heating, you can avoid underfloor heating, so a manageable investment in a few radiators and pipes would not be a problem.
But underfloor heating with large point loads is quite complicated to implement, isn’t it? We’re talking about 2 tons on just a few cm² (square inches), which heating coils probably don’t like.
It’s good to know there is a condensate drain at the heat exchanger, thank you.
@Mycraft
And so far no problems or required cleaning of the controlled mechanical ventilation ducts due to condensate buildup there? Which model/manufacturer did you install? Filters at the exhaust vents in the rooms? In general, it would be interesting to hear about proven manufacturers and models for the entire project—your heating system, solar thermal elements, ventilation, and air conditioning. Feel free to share via private message, thanks!
@fragg
I would prefer not to use underfloor heating for cooling. On one hand, it doesn’t seem physically reasonable to cover cooling via the lowest surface in the room without ventilation above it; on the other hand, I don’t want the floor to be the coldest point. Your feet would get frozen^^ Better to have a full air conditioning system. That also provides the benefit of draining warm and humid air, which is what makes the climate change feel quick and noticeable—not just the cooler air. With AC, at least you know exactly where the condensate will occur. I definitely don’t want that on the floor.
K
Knallkörper16 Jul 2018 20:07I would also tend to avoid cooling through underfloor heating. A cooling coil integrated into the mechanical ventilation with heat recovery system is, of course, possible, but the cooling capacity is rather limited due to the relatively low air volume flow rates. (For my personal needs, however, this would be sufficient, as the cooling load in shaded rooms is not high and it is not necessary to reach 17°C (63°F).)
Regarding condensation, I would have little concern with a centralized mechanical ventilation with heat recovery system. Condensate forms at the cooling coil. Humidity in the rooms decreases. Condensation in the ducts can only occur if there is a sudden switch to uncooled, unconditioned, warm and humid outside air, which is essentially a control-related non-issue.
Regarding condensation, I would have little concern with a centralized mechanical ventilation with heat recovery system. Condensate forms at the cooling coil. Humidity in the rooms decreases. Condensation in the ducts can only occur if there is a sudden switch to uncooled, unconditioned, warm and humid outside air, which is essentially a control-related non-issue.
There are no problems; everything works as it should. As users before me have mentioned, condensation does not occur in the ducts of a mechanical ventilation with heat recovery system, unless there has been poor workmanship.
Condensation in a mechanical ventilation with heat recovery system forms in the heat exchanger, where there is usually a drain.
I have a Wolf CWL-300, but I would also consider installing models from the full range of Helios, Zehnder, etc. It depends on the price. The systems are about 90% the same internally.
Filters are located in the exhaust air vents and, of course, within the unit itself.
The heating system is from Junkers, which is now Bosch.
The air conditioning was added later and is from Honeywell. However, if I were to build again, I would choose Daikin. The Daikin runs very quietly.
Condensation in a mechanical ventilation with heat recovery system forms in the heat exchanger, where there is usually a drain.
I have a Wolf CWL-300, but I would also consider installing models from the full range of Helios, Zehnder, etc. It depends on the price. The systems are about 90% the same internally.
Filters are located in the exhaust air vents and, of course, within the unit itself.
The heating system is from Junkers, which is now Bosch.
The air conditioning was added later and is from Honeywell. However, if I were to build again, I would choose Daikin. The Daikin runs very quietly.
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