With demand-controlled central ventilation, the various rooms in a dwelling receive ventilation where needed. There are two options for demand-controlled ventilation:
- time-driven
- air-quality driven
The first way of demand-controlled ventilation is time driven, with a time switch. The ventilation demand per room can be set to the daytime rhythm of the resident(s). In most cases, for instance, more ventilation is required in the bedroom at night, while during the day the living room needs a supply of fresh air more often.
In the second way of demand-controlled ventilation, the ventilation is automatically controlled on the basis of the concentration of CO2 in a room. Where that value is high (or above the set value), the air quality is too low, so the system automatically feeds in extra fresh air in order to improve the air quality in the room in question. As an option, the moisture content can also be included in the calculation of the air quality. In that case, a relative humidity (RH) sensor is added to the system as an accessory. So the ventilation demand in a room is not determined by the capacity (in m3), but is driven by the air quality in the room. Ventilation is provided only when and where needed, so ventilation is more effective, plus less energy is consumed.
Demand-controlled ventilation can be integrated into a heat-recovery ventilation system. The basis for this system is a central ventilation solution, such as the Flair or the Renovent.
Adjusting the quantity of fresh ventilation air to the demand is controlled by the patented 3-way valve. This electrically-operated valve has different positions and ensures that the ventilation air in the supply ducts is metered when it is fed to the different zones. In that way, the available fresh ventilation air is sent to the room where it is required.
Demand-controlled ventilation is more effective than manual ventilation. With a manual system, the position of the ventilation system is often determined by the user’s experience, rather than a measurement of the air quality. The result of this is often unnecessarily high energy consumption, sub-optimal air quality or both. Apart from that, a demand-controlled system also has the option of changing the system manually, or temporarily to the highest setting, during a party for instance.
