modelBoilerPolynomial

Information

This model represents a steam boiler that discharges saturated steam and has an efficiency curve defined by a polynomial. The efficiency in this model represents the fuel-to-water efficiency (e.g., thermal efficiency). This model is similar to the Buildings.Fluid.Boilers.BoilerPolynomial for the efficiency and fuel mass flow rate computation with the following exceptions:

• June 17, 2026, by Michael Wetter:
  Updated implementation to allow a flow coefficient n that is different from 2. This allows use of the model for not fully turbulent flow.
  This is for Buildings, #4620.
• Water enters port_a in liquid state and exits port_b in vapor state.
• The liquid and vapor phases are at equilibrium; thus, the steam boiler is constrained to saturated states only with the volume containing a wet steam mixture.
• If the boiler is configured in steady state, several blocks involving the heat flow rate are conditionally removed to avoid overconstraining the model. This is because the discharging fluid is constrained at a saturated state. The blocks that are conditionally removed as a result are within the green region in the below figure:

Implementation

In order to improve the numerical efficiency, this model follows the split-medium approach using the Buildings.DHC.BaseClasses.Steam.PartialTwoPortTwoMedium interface model. The saturated mixing volume for an evaporation process Buildings.DHC.Plants.Steam.BaseClasses.ControlVolumeEvaporation represents the phase change process of water from liquid to vapor at equilibrium.

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

Connectors

Components

Contents

Name	Description
MediumWat	Water medium - port_a (inlet)
MediumSte	Steam medium - port_b (oulet)

Revisions

• September 15, 2023, by Kathryn Hinkelman:
  Updated publication references.
• February 25, 2022 by Kathryn Hinkelman:
  Refactored base classes for improved extensibility and relocated models into Steam subpackages.
• July 22, 2021 by Kathryn Hinkelman:
  First implementation.