Hello,
My husband and I are currently trying to decide which heating system to install in our planned house.
I insist on having a ventilation system and a wood-burning stove in the living room. So the heating should be compatible with these.
Our chosen construction company has now offered us three heat pumps:
Air-to-water heat pump: Nibe F2040-8 with Nibe VVM320
Exhaust air heat pump: Nibe F750 P with supply air module SAM 40
Ground source heat pump: Nibe 1245-6 with deep drilling
My husband currently prefers the exhaust air heat pump because he thinks it works like the air-to-water heat pump but makes better use of the warm air from running computers... Everywhere I read, though, it says: "Avoid exhaust air heat pumps unless you are building a passive house."
Does the supply air module actually make it function somewhat like an air-to-water heat pump, but with better use of the warm indoor air?
The house is planned as a two-story timber frame construction with KfW 55 standard. To be honest, I am completely overwhelmed by this complicated heating topic. The more information I get, the more complex it seems.
My husband and I are currently trying to decide which heating system to install in our planned house.
I insist on having a ventilation system and a wood-burning stove in the living room. So the heating should be compatible with these.
Our chosen construction company has now offered us three heat pumps:
Air-to-water heat pump: Nibe F2040-8 with Nibe VVM320
Exhaust air heat pump: Nibe F750 P with supply air module SAM 40
Ground source heat pump: Nibe 1245-6 with deep drilling
My husband currently prefers the exhaust air heat pump because he thinks it works like the air-to-water heat pump but makes better use of the warm air from running computers... Everywhere I read, though, it says: "Avoid exhaust air heat pumps unless you are building a passive house."
Does the supply air module actually make it function somewhat like an air-to-water heat pump, but with better use of the warm indoor air?
The house is planned as a two-story timber frame construction with KfW 55 standard. To be honest, I am completely overwhelmed by this complicated heating topic. The more information I get, the more complex it seems.
Saruss schrieb:
Unfortunately, the heat capacity of air is very low, so a large amount of exhaust air must be extracted. How is this replaced? With fresh, cold air from outside. To prevent the interior from getting cold, this air must also be heated with the help of the heating system. This requires even more exhaust air, and so on. I believe that mechanical ventilation with heat recovery systems have an efficiency of about 90%.
There are two such systems in the neighborhood here. So far, their energy consumption figures look quite promising, although the really cold winters haven’t occurred yet.
Musketier schrieb:
I believe controlled residential ventilation systems have an efficiency of around 90%.
We have two such systems in our neighborhood. So far, the energy consumption figures look quite promising, even though the really cold winters haven’t happened yet. I think you are referring to something different than I am. An exhaust air heat pump is a different system from controlled residential ventilation.
Once the exhaust air heat pump has extracted heat from the air, there is not much left for heat exchange.
Musketier schrieb:
Don’t they advertise that both are combined there?
Also, the COP of 2 is assumed to be quite low, isn’t it? Not combined like with a mechanical ventilation system with heat recovery; that’s not possible.
The higher the COP, the worse the concept becomes. Imagine the COP is 5; then the exhaust air pump must extract 4.8 kW (16,400 BTU) of heat from the air, instead of 3 kW (10,200 BTU) for a 6 kW (20,500 BTU) heat output for the house. That means an even larger volume of air needs to be moved (and much more cold air will have to enter).
Grym schrieb:
But not like with a mechanical ventilation system with heat recovery. With an exhaust air heat pump, the fresh air comes in through outside air vents, so it will be cold in winter or very hot in summer. She has already mentioned several times that they were offered a supply air module. In this system, supply and exhaust air are centrally ducted. The supply air can also be preheated. So, there are not multiple vents in the rooms.
Regarding the water tank: 180 liters (48 gallons) refers to the hot water. Cold water is added on top of that.
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