Bypass, Constant and variable recirculating air proportion

Various flow rates

Ventilation systems with very various flow rates

Ventilation systems
with very various flow rates

On systems with very different air flow rates (Outdoor air / Outgoing air > 1.5) it is recommendable to branch off a portion of the largest air flow and to route it past the rotorsystem.

Ventilation systems with bypass for summer operation

Ventilation systems
with bypass for summer operation

During the rotor stands still (summer operation or maintenance) it should be protected against one way admission of the warm air- / gas stream. Therefore it is recommended to install a bypass on the outgoing air side.

Ventilation systems with constant recirculating air proportion

Ventilation systems
with constant recirculating air proportion

On systems of which only a part of the total air amount is outdoor air, the installation of the rotor system is done only for the outdoor air proportion and for the respective outgoing air amount. The recirculating air proportion is mixed into the outgoing air direction before entering the rotorsystem.

Ventilation systems with variable recirculating air proportion

Ventilation systems
with variable recirculating air proportion

On systems of which the outdoor air part of the total air amount is increased with rising outdoor air temperatures, the construction of the rotorsystem is done only for the minimum outdoor air amount and for respective outgoing air flow rate.

If the rotorsystem is designed for the total air amount, then no bypass is necessary. If only a minimal amount of air is passed through the rotor during winter operation, the temperature efficiency increases and the pressure drop goes down.