modelReheat

Model that implements an on and off controller for a reheater

Information

This model can be used to generate on/off signal for the reheater inside the AHU.

This reheater will be on only if the following two conditions are satisfied at the same time:

  • The position of the water-side valve reaches its switch point, yValSwi;
  • The difference between the inlet temperature of the reheater and the required outlet temperature setpoint is lower than its critical switch point,dTSwi.

In addition, a deadband and waiting time is used to avoid frequent switching.

Parameters

TypeNameDefaultDescription
RealyValSwiSwitch point for valve signal
RealyValDeaBanDeadband for valve signal
Modelica.Units.SI.TemperatureDifferencedTSwiSwitch point for temperature difference
Modelica.Units.SI.TemperatureDifferencedTDeaBanDeadband for temperature difference
Modelica.Units.SI.TimetWaiWaiting time

Connectors

TypeNameDefaultDescription
Modelica.Blocks.Interfaces.RealInputyValValve position
Modelica.Blocks.Interfaces.RealInputdTTemperature difference
Modelica.Blocks.Interfaces.BooleanOutputyOn and off signal for the reheater

Components

TypeNameDefaultDescription
Modelica.StateGraph.InitialStepWithSignaloffOff
Modelica.StateGraph.StepWithSignalonOn
Modelica.StateGraph.TransitionoffToOnConditions that switch off to on
Modelica.StateGraph.TransitiononToOffConditions that switch on to off
Modelica.StateGraph.StateGraphRootstateGraphRoot

Revisions

  • September 12, 2017 by Yangyang Fu:
    First implementation.