Buildings.DHC.Loads.Steam.BaseClasses

Package with base classes for Buildings.DHC.Loads.Steam

Information

This package contains base classes that are used to construct the models in Buildings.DHC.Loads.Steam.

Extends from Modelica.Icons.BasesPackage (Icon for packages containing base classes).

Package Content

Name	Description
ControlVolumeCondensation	Control volume model exhibiting the condensation process of water
SteamTrap	Steam trap with isenthalpic expansion from high to atmospheric pressure, followed by a isobaric condensation process as flashed steam is brought back to a liquid state
ValveSelfActing	Ideal pressure reducing valve for steam heating systems
Examples	Collection of models that illustrate model use and test models

Buildings.DHC.Loads.Steam.BaseClasses.ControlVolumeCondensation

Control volume model exhibiting the condensation process of water

Information

This model represents a condensation process of water with liquid and vapor phases in equilibrium and at a saturated state. Further information regarding the model formulation and assumptions are in the base class Buildings.DHC.BaseClasses.Steam.PartialSaturatedControlVolume.

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

Extends from Buildings.DHC.BaseClasses.Steam.PartialSaturatedControlVolume (Partial control volume for evaporation/condensation processes).

Parameters

Connectors

Modelica definition

Buildings.DHC.Loads.Steam.BaseClasses.SteamTrap

Steam trap with isenthalpic expansion from high to atmospheric pressure, followed by a isobaric condensation process as flashed steam is brought back to a liquid state

Information

The steam trap ensures that only liquid condensate leaves the component, while any flashed steam is returned to a liquid state before discharge. The model assumes a steady state isenthalpic thermodynamic process that transforms water from an upstream high pressure state to atmospheric pressure, followed by an isobaric condensation process as flashed steam vapor is returned to a liquid state. This implementation is consistent with physical valves that vent to the atmosphere.

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

Extends from Buildings.Fluid.Interfaces.PartialTwoPortInterface (Partial model with two ports and declaration of quantities that are used by many models).

Parameters

Connectors

Modelica definition

Buildings.DHC.Loads.Steam.BaseClasses.ValveSelfActing

Ideal pressure reducing valve for steam heating systems

Information

This is the model of self-acting control valve that automatically adjusts the diameter of valve orifice to reduce the unregulated inlet pressure to a constant, reduced outlet pressure.

Implementation

To simplify the complex relationships of the valve opening (y_actual), mass flow rate (m_flow), and change in pressure (dp) for compressible medium (such as steam), this model is implemented using an ideal source Buildings.Fluid.Movers.BaseClasses.IdealSource, that allows the pressure drop to be prescribed independently of mass flow rate.

The model maintains dp based on the user specified downstream pressure value (pb_nominal), except for instances where the upstream pressure falls below pb_nominal. In these instances, the valve exibits no pressure drop (dpSet = 0) and asserts a warning. This model assumes that dp across the valve is independent of m_flow. This generally leads to a simplier set of equations.

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

Extends from Buildings.Fluid.Interfaces.PartialTwoPortInterface (Partial model with two ports and declaration of quantities that are used by many models).

Parameters

Connectors

Modelica definition