.Buildings.DHC.ETS.Combined.Controls.SideHot

Information

This block serves as the controller for the hot 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 controller for heat rejection is enabled when the return position of the evaporator loop isolation valve is close to zero. When enabled, it maintains the temperature at the top of the heating water tank at the heating water supply temperature set point plus a dead band dTDea. The controller yields a control signal value between 0 and nSouAmb. The systems serving as ambient sources are then controlled in sequence by mapping the controller output to a nSouAmb-array of signals between 0 and 1.
• Control signal for cold rejection yCol
  The controller for cold rejection is enabled if
  • the return position of the condenser loop isolation valve is close to zero, and
  • heating is enabled, and
  • the temperature at the top of the heating water tank is below a safety limit equal to the heating water supply temperature set point plus the parameter dTLoc. This last condition limits the temperature overshoot after the warmup periods, without having to finely tune the heat and cold rejection controller parameters to guard against the disturbing effect of a varying district water temperature.
  When enabled, the controller maintains the temperature at the top of the heating water tank at the heating water supply temperature set point. The controller yields a signal between 0 and nSouAmb+1 which is connected to Buildings.DHC.ETS.Combined.Controls.SideCold where it is used to control in sequence the systems serving as ambient sources and ultimately to reset down the chilled water supply temperature.
• Control signal for the condenser loop isolation valve yIsoAmb
  The valve is commanded to be fully open whenever the controller for heat rejection yields an output signal 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.
• March 6, 2025, by Hongxiang Fu:
  Added uCoo as an additional condition to enable conHeaRej.
  This is for #4133.
• 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.