.Buildings.Templates.Plants.Controls.MinimumFlow.ControllerDualMode

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.

Revisions

• May 31, 2024, by Antoine Gautier:
  First implementation.