blockControllerDualMode
Information
HW minimum flow
The HW minimum flow bypass valve is modulated based on a reverse acting control loop to maintain the primary HW flow rate at setpoint. The setpoint is calculated as described in Buildings.Templates.Plants.Controls.MinimumFlow.Setpoint using the number of units commanded on in heating mode at each stage.
When using isolation valve command signals
(have_valInlIso=true or have_valOutIso=true):
When any HW isolation valve is commanded open, the HW bypass valve control loop is enabled.
The valve is opened 100 % otherwise.
When enabled, the HW bypass valve loop shall be biased to start with the valve 100 % open.
Otherwise
(have_valInlIso=false and have_valOutIso=false):
- For heating and cooling plants with common dedicated CHW and HW pumps: When any primary pump is proven on and the associated heat pump is commanded in heating mode, the HW bypass valve control loop is enabled. The valve is opened 100 % otherwise. When enabled, the HW bypass valve loop shall be biased to start with the valve 100 % open.
- For any other plants: When any primary HW pump is proven on, the HW bypass valve control loop is enabled. The valve is opened 100 % otherwise. When enabled, the HW bypass valve loop shall be biased to start with the valve 100 % open.
CHW minimum flow
The CHW minimum flow bypass valve is modulated based on a reverse acting control loop to maintain the primary CHW flow rate at setpoint. The setpoint is calculated as described in Buildings.Templates.Plants.Controls.MinimumFlow.Setpoint using the number of units commanded on in cooling mode at each stage.
When using isolation valve command signals
(have_valInlIso=true or have_valOutIso=true):
When any CHW isolation valve is commanded open, the CHW bypass valve control loop is enabled.
The valve is opened 100 % otherwise.
When enabled, the CHW bypass valve loop shall be biased to start with the valve 100 % open.
Otherwise
(have_valInlIso=false and have_valOutIso=false):
- For heating and cooling plants with common dedicated CHW and HW pumps: When any primary pump is proven on and the associated heat pump is commanded in cooling mode, the CHW bypass valve control loop is enabled. The valve is opened 100 % otherwise. When enabled, the CHW bypass valve loop shall be biased to start with the valve 100 % open.
- For any other plants: When any primary CHW pump is proven on, the CHW bypass valve control loop is enabled. The valve is opened 100 % otherwise. When enabled, the CHW bypass valve loop shall be biased to start with the valve 100 % open.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | have_heaWat | Set to true for plants that provide HW | |
| Boolean | have_chiWat | Set to true for plants that provide CHW | |
| Boolean | have_pumChiWatPri | Set to true for plants with separate primary CHW pumps | |
| Boolean | have_valInlIso | Set to true to enable control loop based on inlet isolation valve command | |
| Boolean | have_valOutIso | Set to true to enable control loop based on outlet isolation valve command | |
| Integer | nEqu | 0 | Number of plant equipment |
| Integer | nEnaHeaWat | 0 | Number of enable signals for HW loop – Valve command or pump status |
| Integer | nEnaChiWat | nEnaChiWat | Number of enable signals for CHW loop – Valve command or pump status |
| Real[nEqu] | VHeaWat_flow_nominal | Design HW flow rate – Each unit | |
| Real[nEqu] | VHeaWat_flow_min | Minimum HW flow rate – Each unit | |
| Real[nEqu] | VChiWat_flow_nominal | Design CHW flow rate – Each unit | |
| Real[nEqu] | VChiWat_flow_min | Minimum CHW flow rate – Each unit | |
| Real | k | 1 | Gain of controller |
| Modelica.Units.SI.Time | Ti | 0.5 | Time constant of integrator block |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Interfaces.RealInput | VChiWatPri_flow | Primary CHW volume flow rate | |
| Buildings.Controls.OBC.CDL.Interfaces.RealInput | VHeaWatPri_flow | Primary HW volume flow rate | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput[nEnaHeaWat] | u1PumHeaWatPri_actual | Primary HW pump status | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput[nEnaHeaWat] | u1ValHeaWatInlIso | Equipment inlet HW isolation valve command | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput[nEnaHeaWat] | u1ValHeaWatOutIso | Equipment outlet HW isolation valve command | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | yValHeaWatMinByp | HW minimum flow bypass valve command | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput[nEqu] | u1Equ | Equipment enable command | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | VHeaWatPriSet_flow | Primary HW flow setpoint | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput[nEqu] | u1HeaEqu | Equipment heating/cooling mode command | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput[nEnaChiWat] | u1PumChiWatPri_actual | Primary CHW pump status | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput[nEnaChiWat] | u1ValChiWatInlIso | Equipment inlet CHW isolation valve command | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput[nEnaChiWat] | u1ValChiWatOutIso | Equipment outlet CHW isolation valve command | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | yValChiWatMinByp | CHW minimum flow bypass valve command | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | VChiWatPriSet_flow | Primary CHW flow setpoint |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Controller | ctlFloMinHeaWat | HW minimum flow control | |
| Controller | ctlFloMinChiWat | CHW minimum flow control | |
| Utilities.PlaceholderLogical[nEqu] | phHeaCoo | Placeholder signal for single mode applications | |
| Buildings.Controls.OBC.CDL.Logical.Not[nEqu] | u1Coo | True if cooling mode | |
| Buildings.Controls.OBC.CDL.Logical.And[nEqu] | onAndHea | True if commanded on in heating mode | |
| Buildings.Controls.OBC.CDL.Logical.And[nEqu] | onAndCoo | True if commanded on in cooling mode | |
| Utilities.PlaceholderLogical[nEnaChiWat] | phPumChiWatPri | Use CHW pump signal in case the plant does not have common CHW and HW dedicated pumps | |
| Buildings.Controls.OBC.CDL.Logical.And[nEqu] | pumOnAndCoo | True if pump proven on and equipment in cooling mode – Case with common CHW and HW dedicated pumps | |
| Buildings.Controls.OBC.CDL.Logical.And[nEqu] | pumOnAndHea | True if pump proven on and equipment in heating mode – Case with common CHW and HW dedicated pumps | |
| Utilities.PlaceholderLogical[nEnaHeaWat] | phPumHeaWatPri | Use HW pump signal in case the plant does not have common CHW and HW dedicated pumps |
Revisions
-
May 31, 2024, by Antoine Gautier:
First implementation.