ᐅ Ventilation system with heat recovery, installation location temperature
Created on: 24 Nov 2017 11:54
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Vwgolfcabrio
Hello,
I have a central ventilation system with heat recovery installed in the attic of my new build. The attic is insulated but only has a small radiator that provides limited heating at a flow temperature of about 32°C (90°F). In winter, the attic temperature is around 14-15°C (57-59°F). Now my question:
Does it make sense to increase the temperature in the attic (for example, by installing larger radiators)? Would the system then operate more efficiently, meaning the temperature supplied to the rooms would increase and would I save heating energy as a result?
Thank you very much.
Best regards, Fabian
I have a central ventilation system with heat recovery installed in the attic of my new build. The attic is insulated but only has a small radiator that provides limited heating at a flow temperature of about 32°C (90°F). In winter, the attic temperature is around 14-15°C (57-59°F). Now my question:
Does it make sense to increase the temperature in the attic (for example, by installing larger radiators)? Would the system then operate more efficiently, meaning the temperature supplied to the rooms would increase and would I save heating energy as a result?
Thank you very much.
Best regards, Fabian
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Goldi0911126 Nov 2017 23:49Is it true that a mechanical ventilation system with heat recovery should not be installed in an uninsulated attic?
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readytorumble27 Nov 2017 07:09As already mentioned, the Pluggit system requires a temperature of 12°C (54°F) at the installation site throughout the year.
The ventilation technician had to confirm this in the commissioning report (in our case, my brother-in-law, since it was a DIY project).
The ventilation technician had to confirm this in the commissioning report (in our case, my brother-in-law, since it was a DIY project).
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Bieber081527 Nov 2017 10:52Vwgolfcabrio schrieb:
When I open the roof hatch in my house, the temperature in the attic rises, and the air being blown out increases to around 20/21°C (68/70°F). When the hatch is closed and the attic temperature is only 15°C (59°F), the blown-out air temperature is about 16°C (61°F). Interesting, I wouldn’t have expected that. Do you have a leak in the supply duct in the attic? I can’t really make sense of this without knowing more about your system.
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Vwgolfcabrio27 Nov 2017 13:06Hello, in the attic where the system is located, there are both supply and exhaust air vents. The exhaust air drawn from the attic is naturally colder than from the other rooms in the house. If I leave the attic hatch open, the temperature in the attic rises, and warmer air is also exhausted! That is why I am considering enlarging the radiator in the attic to increase the system’s efficiency.
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Bieber081527 Nov 2017 13:19Vwgolfcabrio schrieb:
That’s why I’m considering enlarging the radiator in the attic to increase the system’s efficiency? Now I understand which temperatures you mean. No, that does not increase efficiency. The degree of heat recovery is always less than 1. For every additional kW you feed into the attic heating, you only get a part of it back. The rest is lost.
I believe this remains the case even when looking at the entire system (i.e., the balance of the entire mechanical ventilation with heat recovery, not just the attic), but I’m currently too lazy to calculate it or come up with the necessary assumptions :P.
The exhaust air from the attic is only a (small) part of the total outgoing air.
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