.DisHeatLib.Substations.BaseStations.IndirectStation

Information

This is a model for an indirect district heating substation. Its main components are a heat exchanger, a flow regulating valve, a pump to deliver heat to the customers, an expansion vessel and controller that maintains the temperature at the secondary side by setting the position of the flow regulating valve/pump. The supply temperature setpoint at the secondary side can thereby be set to a constant or can be changed depending on the outside temperature.

A mismatch between the setpoint and the actual value of the secondary supply temperature can have different reasons:

• The differential pressure at the station is too low, resulting in a too low mass flow at the primary side even if the valve is completely open.
• The nominal mass flow rate at the primary side is too low, leading to a too low secondary supply temperature even with a fully opend valve.
• The supply temperature at the primary side is too low, i.e., lower than the secondary supply temperature setpoint, leading to a fully opened valve.

Redimensioning the substation, e.g., by using a more efficient heat exchanger or a higher differential pressure at the primary side, might solve these issues.

Revisions

• Feburary 27, 2019, by Benedikt Leitner:
  Implementation and added User's guide.