modelCtrAHUCO2
Controller for AHU with CO2-control
Information
This control uses the heating and cooling register to regulate the supply air temperature. The set point of the supply air can be given either by the parameter TFlowSet or by the external input variable Tset. The preheater is used for frost protection and has a fixed set point of 5°C. The heat recovery system is always used and the bypass closed. The supply and return air flaps are always open.
The volume flow is controlled by PID controllers with two options:
- useTwoFanCtr = False: the supply and return air fans are controlled by only one PID controller. Both fans get the same pressure setpoint. This option is recommended for closed systems where the supply air volume flow is equal to the return air volume flow. Without this option, only one fan could be active to provide volume flow.
- useTwoFanCtr = True: The supply air fan and the return air fan are controlled separately. Each controller aims to reach the volume flow set point for the supply or return air chanal. This option is recommended for open systems.
The maximal volume flow can be limited by the maximal pressure difference of the fans dpMax.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Temperature | TFlowSet | 289.15 | Flow temperature set point of consumer |
| Boolean | usePreheater | true | Set true, if ahu contains a preaheater |
| Real | TFrostProtect | 273.15 + 5 | Temperature set point of preheater for frost protection |
| Real | relHumSupSet | 0.6 | Set point for steam humidifier for relative humidity |
| Boolean | useExternalTset | false | If True, set temperature can be given externally |
| Modelica.Units.SI.VolumeFlowRate | Vflow_nominal | 3000/3600 | Nominal value of volume flow [m^3/s] |
| Real | minVflowPer | 0.3 | Minimal percentage volume flow |
| Real | CO2set | 800 | Set value of CO2 concentration in ppm |
| Real | dpMax | 5000 | Maximal pressure difference of the fans [Pa] |
| Boolean | useTwoFanCtr | false | If True, a PID for each of the two fans is used. Use two PID controllers for open systems (if the air canal is not closed). |
| Real | k | 50 | Gain of Vflow controller |
| Modelica.Units.SI.Time | Ti | 5 | Time constant of Integrator block Vflow |
| Real | kCO2 | Vflow_nominal/1000 | Gain of CO2 controller |
| Modelica.Units.SI.Time | TiCO2 | 300 | Time constant of Integrator block CO2 |
| Real | y_start | 0 | Initial value of output |
| Modelica.Blocks.Types.Init | initType | Modelica.Blocks.Types.Init.NoInit | Type of initialization (1: no init, 2: steady state, 3: initial state, 4: initial output) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| CtrRegBasic | ctrPh | ||
| CtrRegBasic | ctrCo | ||
| CtrRegBasic | ctrRh | ||
| BaseClasses.GenericAHUBus | genericAHUBus | Bus connector for genericAHU | |
| Modelica.Blocks.Sources.Constant | constTflowSet | ||
| Modelica.Blocks.Interfaces.RealInput | Tset | Connector of set temperature, if given externally | |
| Modelica.Blocks.Sources.Constant | TFrostProtection | ||
| Controls.Continuous.LimPID | PID_VflowSup | PID controller for supply fan | |
| Controls.Continuous.LimPID | PID_VflowRet | PID controller for return fan. Is deactivated if useTwoFanCtr is false. | |
| Modelica.Blocks.Sources.Constant | ConstHRS | Heat recovery is deactivated | |
| Modelica.Blocks.Sources.Constant | ConstFlap | Flaps are always open | |
| Modelica.Blocks.Sources.Constant | ConstHum | Humidifiers are off | |
| Controls.Continuous.LimPID | PID_CO2 | PID controller for CO2 concentration | |
| Modelica.Blocks.Sources.Constant | constCO2Set | ||
| Modelica.Blocks.Interfaces.RealInput | CO2Mea | measurement input signal for CO2 concentration | |
| Modelica.Blocks.Routing.RealPassThrough | realPassThrough | ||
| Controls.Continuous.LimPID | PID_SteamHum | PID controller for supply fan | |
| Modelica.Blocks.Sources.Constant | constRelHumSup |
Revisions
- October 29, 2019, by Alexander Kümpel:
First implementation