.Buildings.DHC.ETS.Combined.Controls.SideCold

Information

This block serves as the controller for the cold side of the ETS in Buildings.DHC.ETS.Combined.Controls.Supervisory. It computes the following control signals.

• Control signals for ambient sources yAmb (array)
  The cold rejection control signal yielded by the hot side controller is processed as follows.
  • A controller is used to track the chilled water supply temperature (CHWST) set point. This controller is enabled when cooling is enabled. It yields a control signal value between 0 and nSouAmb.
  • The systems serving as ambient sources are then controlled in sequence by mapping the minimum between the CHWST control loop output and the part of the cold rejection signal between 0 and nSouAmb to a nSouAmb-array of signals between 0 and 1.
• Chilled water supply temperature set point TChiWatSupSet
  The remaining part of the cold rejection signal between nSouAmb and nSouAmb+1 is used to reset the CHWST set point between a maximum value provided as an input variable, and a minimum value provided as a parameter.
• Control signal for the evaporator loop isolation valve yIsoAmb
  The valve is commanded to be fully open whenever the cold rejection control signal is greater than zero. The command signal is held for 5 min to avoid short cycling.

Revisions

• March 7, 2025, by Michael Wetter:
  Increased, and added where missing, hysteresis, as the input signal is the output of the PID controller.
• November 22, 2024, by Michael Wetter:
  Reduced number of time events by replacing zero order hold with true and false hold, and increasing the minimum cycle time.
  This is for #4058.
• July 31, 2020, by Antoine Gautier:
  First implementation.