ᐅ Please review my mechanical ventilation system design for residential buildings.
Created on: 21 Feb 2019 09:50
C
Christian NWHello everyone,
could you please review my mechanical ventilation with heat recovery (MVHR) system design?
Objectives:
1. Good air quality in all rooms
2. A system that is absolutely quiet and hardly audible in the rooms
Questions:
1. Are the airflow rates sufficient?
2. Is the system barely audible?
3. ...
Thanks in advance!!
Attached are the planning documents.
We are using the RecoVair 360/4 from Vaillant.
Hello Christian,
In my opinion, floor-level outlets are not recommended. They cause dust convection, and the air entering the house is always a few degrees cooler than the existing air, so it immediately sinks. A ceiling diffuser or a wall vent placed in the upper third of the room would be better. The requirement is 45 m³/h (approximately 26.5 CFM) for both kitchen and bathroom. So, with a 75 mm (3 inch) flexible duct, you need to use two ducts leading to one vent to keep the air velocity below 2.5 m/s (about 8.2 ft/s) and thus avoid drafts.
Alternatively, and even better, install two exhaust vents per exhaust room, each connected to a single duct. This would also ensure better distribution of the exhaust air within the room.
I also notice the absence of a sound attenuator in the exhaust air duct to the wall.
As a recommendation, never design for more than 30 m³/h (about 17.6 CFM) per 75 mm (3 inch) flexible duct.
My device recommendation is exclusively rotary heat exchangers.
Advantages:
Moisture recovery, no system-related electric preheating needed in winter, no condensate, and pollen filter as standard from the factory.
Best regards,
HIGIL
In my opinion, floor-level outlets are not recommended. They cause dust convection, and the air entering the house is always a few degrees cooler than the existing air, so it immediately sinks. A ceiling diffuser or a wall vent placed in the upper third of the room would be better. The requirement is 45 m³/h (approximately 26.5 CFM) for both kitchen and bathroom. So, with a 75 mm (3 inch) flexible duct, you need to use two ducts leading to one vent to keep the air velocity below 2.5 m/s (about 8.2 ft/s) and thus avoid drafts.
Alternatively, and even better, install two exhaust vents per exhaust room, each connected to a single duct. This would also ensure better distribution of the exhaust air within the room.
I also notice the absence of a sound attenuator in the exhaust air duct to the wall.
As a recommendation, never design for more than 30 m³/h (about 17.6 CFM) per 75 mm (3 inch) flexible duct.
My device recommendation is exclusively rotary heat exchangers.
Advantages:
Moisture recovery, no system-related electric preheating needed in winter, no condensate, and pollen filter as standard from the factory.
Best regards,
HIGIL