.Buildings.DHC.ETS.Combined.Controls.Borefield

Information

This block implements the control logic for the borefield system. The main control signal u is yielded by the hot side or cold side controller, see for instance Buildings.DHC.ETS.Combined.Controls.SideHot.

The system is enabled when

• the main control signal is greater than zero,
• the return position of at least one isolation valve is greater than 90%.

When the system is enabled,

• the input signal is mapped to modulate in sequence the mixing valve (from full bypass to closed bypass for a control signal varying between 0% and 30%) and the pump speed (from the minimum to the maximum value for a control signal varying between 30% and 100%),
• a PI loop tracks the maximum inlet temperature, the minimum between this loop output and the previously mapped signal being used to modulate the valve.

Note that the first control signal for the valve is needed to stabilize the control of the system when the mass flow rate required to meet the heat or cold rejection demand is below the flow rate corresponding to the minimum pump speed.

Revisions

• July 31, 2020, by Antoine Gautier:
  First implementation.