modelDistributionCondensatePipe
Extends from Buildings.DHC.Networks.BaseClasses.PartialDistribution2Pipe2Medium (Partial model for a two-pipe distribution network with two medium declarations).
Information
This is a model of a distribution network for steam heating systems. The model utilizes a split-medium approach with two separate medium declarations between liquid (condensate return) and vapor (steam supply) states. The piping network features:
- a connection model with fixed hydraulic resistance and no heat loss in the condensate return pipe segments;
- a dummy pipe model with no hydraulic resistance and no heat loss for the steam supply pipes; and
- a dummy pipe model with no hydraulic resistance and no heat loss for the end of the distribution line (after the last connection).
References
Kathryn Hinkelman, Saranya Anbarasu, Michael Wetter, Antoine Gautier, Wangda Zuo. 2022. “A Fast and Accurate Modeling Approach for Water and Steam Thermodynamics with Practical Applications in District Heating System Simulation,” Energy, 254(A), pp. 124227. 10.1016/j.energy.2022.124227
Kathryn Hinkelman, Saranya Anbarasu, Michael Wetter, Antoine Gautier, Baptiste Ravache, Wangda Zuo 2022. “Towards Open-Source Modelica Models For Steam-Based District Heating Systems.” Proc. of the 1st International Workshop On Open Source Modelling And Simulation Of Energy Systems (OSMSES 2022), Aachen, German, April 4-5, 2022. 10.1109/OSMSES54027.2022.9769121
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | show_heaFlo (from PartialDistribution2Pipe2Medium) | false | Set to true to output the heat flow rate transferred to each connected load |
| Real | n | 2 | Flow exponent, n=1 for laminar, n=2 for turbulent |
| General | |||
| Integer | nCon (from PartialDistribution2Medium) | Number of connections | |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialDistribution2Medium) | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| General › Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | mDis_flow_nominal (from PartialDistribution2Pipe2Medium) | Nominal mass flow rate in the distribution line before the first connection | |
| Modelica.Units.SI.MassFlowRate[nCon] | mCon_flow_nominal (from PartialDistribution2Pipe2Medium) | Nominal mass flow rate in each connection line | |
| Modelica.Units.SI.MassFlowRate | mEnd_flow_nominal (from PartialDistribution2Pipe2Medium) | mDis_flow_nominal - sum(mCon_flow_nominal) | Nominal mass flow rate in the end of the distribution line |
| Modelica.Units.SI.MassFlowRate[nCon] | mDisCon_flow_nominal (from PartialDistribution2Pipe2Medium) | cat(1, {mDis_flow_nominal}, {mDis_flow_nominal - sum(mCon_flow_nominal[1:i]) for i in 1:(nCon - 1)}) | Nominal mass flow rate in the distribution line before each connection |
| Dynamics › Equations | |||
| Modelica.Fluid.Types.Dynamics | energyDynamics (from PartialDistribution2Pipe2Medium) | Modelica.Fluid.Types.Dynamics.FixedInitial | Type of energy balance: dynamic (3 initialization options) or steady state |
| Dynamics › Nominal condition | |||
| Modelica.Units.SI.Time | tau (from PartialDistribution2Pipe2Medium) | 10 | Time constant at nominal flow for dynamic energy and momentum balance |
| Nominal condition | |||
| Modelica.Units.SI.PressureDifference | dp_nominal | Pressure drop at nominal mass flow rate | |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPorts_a[nCon] | ports_aCon (from PartialDistribution2Medium) | Connection return ports | |
| Modelica.Fluid.Interfaces.FluidPorts_b[nCon] | ports_bCon (from PartialDistribution2Medium) | Connection supply ports | |
| Modelica.Fluid.Interfaces.FluidPort_a | port_aDisSup (from PartialDistribution2Medium) | Distribution supply inlet port | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_bDisSup (from PartialDistribution2Medium) | Distribution supply outlet port | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_bDisRet (from PartialDistribution2Pipe2Medium) | Distribution return outlet port | |
| Modelica.Fluid.Interfaces.FluidPort_a | port_aDisRet (from PartialDistribution2Pipe2Medium) | Distribution return inlet port |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe2Medium[nCon] | con (from PartialDistribution2Pipe2Medium) | ||
| Model_pipDis | pipEnd (from PartialDistribution2Pipe2Medium) | Pipe representing the end of the distribution line (after last connection) |
Revisions
-
September 15, 2023, by Kathryn Hinkelman:
Updated publication references. -
March 2, 2022, by Kathryn Hinkelman:
First implementation.