Variable Air Volume (VAV) system is nowadays very much important consideration in the lab design and build. VAV system provides the flexibility to control, monitor the lab air requirements. It plays an important role in energy saving and smooth operation of lab air.SbyD represents products of TEL-UK and SCHNEIDER-GERMANY for VAV lab control systems.Velocity based control system - Products of TEL – UK.Volume based control system - Products of Schneider- Germany.
The above schematic shows a fully self-sufficient laboratory control system to flow basis. The fume hoods are controlled with the volume controller iCM-V-E2 on variable air volume basis, depending on the sash position and the air volume flow is available to LCO500 as an analogue signal 0(2)...10V DC.
All remaining exhaust units have their own switchable constant air flow controller (On/Off). All signals (switches) are connected to the digital and analogue inputs of the laboratory controller LCO500 which calculates the room balancing and set values for the room supply air VAV and an additional room exhaust air VAV (it is always necessary when a specific minimum level of room air exchange must be maintained, which can’t be achieved by the extraction units alone).
The direct control of the supply air VAV and the room exhaust air VAV allows the stable tracking of the supply air (supply air = exhaust air - offset) or (supply air = exhaust air -% share). Due to the calculated set point value open doors or windows doesn´t influence the control behavior, i.e. the supply air and exhaust air is stable under all operating conditions.
The analogue inputs, digital inputs and digital outputs are available via the optional network (BACnet, LON or Modbus) to the building management system (BMS). Additionally the BMS can perform a day/night switching to save energy during the night operation (non-working time with reduced air exchange rate).
The duct pressure control iCM DP works in this example also self-sufficient and can either control a bleed damper or a frequency inverter of a blower and is possible for both the total supply air and the total exhaust air.