DistrictHeatConnection
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Use
The model DistrictHeatConnection represents the heat transmission station between a heating grid and one or more consumers.
The DistrictHeatConnection covers the following applications:
Basic: The flow and return temperature information of the heating grid is provided via real expressions.
GridConnection: A full-featured connection to the district heating grid is realized with thermal interfaces of the Blue Energy library.
Parameters and Connectors
Basic
The consumer must be connected to the DistrictHeatConnection via ▶FlowHeatSink and ▶ReturnHeatSink. The reference flow temperature of the consumer (▶TFlowRefHeatSink) can be set via the real input. The flow temperature (▶TFlowGrid) and the reference return temperature (▶TReturnRefGrid) of the district heating grid must also be specified. It must be ensured that the grid flow temperature is higher than the required sink flow temperature.
The required grid volume flow is calculated internally with the parametrized maximum volume flow (qvMax) and the reference return temperature of the district heating grid. The heating medium properties on the grid and consumer side can be specified with the parameters cpMedprim, cpMedsec, rhoMedprim and rhoMedsec.
On the second parameter tab in the dialogue (Heat Exchanger Properties), the usual heat exchanger properties must be defined (AHeatExchanger, Vprim, Vsec, F and k1). These can be found in the corresponding heat exchanger data sheet.
Grid Connection
In this case, if the GridConnection parameter is set to 'true', the connectors ▶FlowGrid and ▶ReturnGrid are available. These can be used to connect a district heating model to the consumer. It must still be ensured that the grid flow temperature is higher than the required sink flow temperature. The reference flow temperature on the consumer side is achieved with a HydraulicValveFlow.
Model Background
The volume flow in the Basic-Case is calculated by a VolumeFlowControllerHeat. It is parametrized with the maximum volume flow and linked to the return temperature to the grid and the reference return temperature. DeltaTup and DeltaTLow are set to (-)2 K.