modelSupply_pT
Extends from DisHeatLib.Supply.BaseClasses.BaseSupply, DisHeatLib.Supply.BaseClasses.ThermalElectricInterface.
Information
General
This supply unit is modeled as a pressure source with a prescribed supply temperature. The delivered pressure lift of this unit is either determined by a fixed set-point or via a PI-controller that receives measurements from the network, e.g., from the weakest point in the network. The supply temperature can be set to be outside temperature controlled or constant. The main supply unit is considered as an ideal heating unit without any constraints regarding mass fow or ramp rates. The maximum heat generation is, however, limited by its nominal heat flow parameter (Q_flow_nominal).
Heat and power
The unit can be modelled as a simple heat and power unit using the characteristic powerCha. Electric power consumption/generation is then set according to the power values corresponding to current heat flow using table entries from the characteristic (and linearly interpolating). Electric power consumption of the pump is also considered. Since the pump is considered to be cooled by the fluid, a one to one conversion between heat added to the fluid and pumping power is considered.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| General › Ports | |||
| Integer | nPorts (from PartialTwoPortVector) | Number of ports | |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialTwoPortVector) | true | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Nominal condition | |||
| Modelica.SIunits.MassFlowRate | m_flow_nominal (from BaseSupply) | Q_flow_nominal/((TemSup_nominal - TemRet_nominal)*cp_default) | Nominal mass flow rate |
| Modelica.SIunits.Power | Q_flow_nominal (from BaseSupply) | Nominal heat flow rate | |
| Modelica.SIunits.Temperature | TemSup_nominal (from BaseSupply) | Nominal supply temperature | |
| Modelica.SIunits.Temperature | TemRet_nominal (from BaseSupply) | Nominal return temperature | |
| Modelica.SIunits.PressureDifference | dp_nominal | Nominal pressure difference of pump | |
| Advanced | |||
| Modelica.SIunits.MassFlowRate | m_flow_small (from BaseSupply) | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow |
| Electric power | |||
| Boolean | isElectric (from ThermalElectricInterface) | true | Unit has electric interface |
| DisHeatLib.Supply.BaseClasses.BasePowerCharacteristic | powerCha (from ThermalElectricInterface) | Characteristic for heat and power units | |
| Supply temperature | |||
| DisHeatLib.Supply.BaseClasses.InputTypeSupplyTemp | SupplyTemperature | DisHeatLib.Supply.BaseClasses.InputTypeSupplyTemp.Constant | Supply temperature type |
| Modelica.SIunits.Temperature | TemOut_min | Outside temperature where maximum supply temperature is used | |
| Modelica.SIunits.Temperature | TemOut_max | Outside temperature where minimum supply temperature is used | |
| Modelica.SIunits.Temperature | TemSup_min | Minimum supply temperature | |
| Modelica.SIunits.Temperature | TemSup_max | Maximum supply temperature | |
| Differential pressure | |||
| Boolean | dp_controller | true | Use differential pressure controller (otherwise constant pressure head, using nominal pressure, between supply and demand is used) |
| Modelica.SIunits.Pressure | dp_min | Minimum differential pressure | |
| Modelica.SIunits.Pressure | dp_set | Differential pressure setpoint | |
| Modelica.SIunits.Pressure | dp_max | Maximum differential pressure | |
| Real | k | 50 | Gain of controller |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_a (from PartialTwoPortVector) | Fluid connector a (positive design flow direction is from port_a to ports_b) | |
| Modelica.Fluid.Interfaces.FluidPorts_b[nPorts] | ports_b (from PartialTwoPortVector) | Fluid connectors b (positive design flow direction is from port_a to ports_b) | |
| Modelica.Blocks.Interfaces.RealOutput | P (from ThermalElectricInterface) | Active power consumption (positive)/generation(negative) | |
| Modelica.Blocks.Interfaces.RealInput | dp_measure | ||
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | port_ht | ||
| Modelica.Blocks.Interfaces.RealInput | TSup_in |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Sources.RealExpression | otherPowerUnits (from ThermalElectricInterface) | Reserved for other power units (e.g., pumps); negative is generation, positive is consumption | |
| Modelica.Blocks.Sources.RealExpression | TSetConst | ||
| Controls.dp_control | dp_control | ||
| Controls.TemSup_control | TsupController | ||
| Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor | outsideTemperatureSensor | ||
| IBPSA.Fluid.Movers.FlowControlled_dp | pump | ||
| IBPSA.Fluid.HeatExchangers.Heater_T | heater | ||
| IBPSA.Fluid.Storage.ExpansionVessel | exp |
Revisions
- Feburary 27, 2019, by Benedikt Leitner:
Implementation and added User's guide.