Proportional Pressure Control For Air Handling Units
volume flow controller without damper position feedback
Due to very limited budgets, volume flow variable RLT systems are often designed without (costly) low pressure measurement. Instead, the pressure sensor is installed cost-effectively directly after the ventilation unit in the technical center. Furthermore, the connected data points are limited by the volumetric flow controller to the VSR control (setpoint volumetric flow) and possibly also to the feedback VSR (actual value volumetric flow). In this case, a pressure setpoint with nominal air quantity is determined with the ventilation engineer.
This design has the decisive disadvantage that in the partial load range, the form pressure for the volumetric flow controller is much too high, since the reduced pressure loss behaves quadratically to the volume flow.
An important advantage of the DIGICONTROL Proportional Pressure Control is that no further data points are required and the pressure detection can still be done in the control center immediately after the ventilation unit.