blockController

Information

Multi zone VAV AHU economizer control sequence that calculates outdoor and return air damper positions based on ASHRAE Guidline 36, PART 5 sections: N.2.c, N.5, N.6.c, N.7, A.17, N.12.

The sequence consists of three subsequences.

• First, the block damLim computes the damper position limits to satisfy outdoor air requirements. See Buildings.Obsolete.Controls.OBC.ASHRAE.G36_PR1.AHUs.MultiZone.VAV.Economizers.Subsequences.Limits for a description.
• Second, the block enaDis enables or disables the economizer based on outdoor temperature and optionally enthalpy, and based on the supply fan status, freeze protection stage and zone state. See Buildings.Obsolete.Controls.OBC.ASHRAE.G36_PR1.AHUs.MultiZone.VAV.Economizers.Subsequences.Enable for a description.
• Third, the block mod modulates the outdoor and return damper position to track the supply air temperature setpoint, subject to the limits of the damper positions that were computed in the above two blocks. See Buildings.Obsolete.Controls.OBC.ASHRAE.G36_PR1.AHUs.MultiZone.VAV.Economizers.Subsequences.Modulation for a description.

To enable freeze protection control logic that closes the outdoor air damper based on the mixed air temperature TMix, set use_TMix=true. This part of the control logic is not in Guideline 36, public review draft 1.

To enable the freeze protection according to Guideline 36, public review draft 1, which may be revised in future versions, set use_G36FrePro=true.

Parameters

Connectors

Components

Revisions

• July 10, 2020, by Antoine Gautier:
  Changed default value of integral time for minimum outdoor air control.
  This is for #2019.
• October 11, 2017, by Michael Wetter:
  Corrected implementation to use control loop signal as input.
• June 28, 2017, by Milica Grahovac:
  First implementation.