Stability Analysis and Mitigation of Thermo-Hydraulic Oscillations in Multi-Supplier District Heating Systems

In fourth-generation district heating systems (DHSs), the supply temperature of modern heat sources such as heat pumps and waste heat can potentially be reduced by mixing in hot water from combustion-based producers, thereby increasing efficiency and facilitating integration into networks with unren...

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Main Authors: Pascal Friedrich, Kirill Kuroptev, Thanh Huynh, Stefan Niessen
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/18/5/1126
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author Pascal Friedrich
Kirill Kuroptev
Thanh Huynh
Stefan Niessen
author_facet Pascal Friedrich
Kirill Kuroptev
Thanh Huynh
Stefan Niessen
author_sort Pascal Friedrich
collection DOAJ
description In fourth-generation district heating systems (DHSs), the supply temperature of modern heat sources such as heat pumps and waste heat can potentially be reduced by mixing in hot water from combustion-based producers, thereby increasing efficiency and facilitating integration into networks with unrenovated buildings. However, this approach introduces the risk of thermo-hydraulic oscillations driven by mixing dynamics, transport delays, and mass flow adjustments by consumers. These oscillations can increase wear and cost and may potentially lead to system failure. This study addresses the asymptotic stability of multi-supplier DHSs by combining theoretical analysis and practical validation. Through linearization and Laplace transformation, we derive the transfer function of a system with two suppliers. Using pole-zero analysis, we show that transport delay can cause instability. We identify a new control law, demonstrating that persisting oscillations depend on network temperatures and low thermal inertia and enabling stabilization through careful temperature selection, thorough choice of the slack supplier, or installation of buffer tanks. We validate our findings using dynamic simulations of a nonlinear delayed system in Modelica, highlighting the applicability of such systems to real-world DHSs. These results provide actionable insights for designing robust DHSs and mitigating challenges in multi-supplier configurations by relying on thoughtful system design rather than complex control strategies.
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spelling doaj-art-99b4be801bb34dec871bfe643c76411a2025-08-20T02:59:14ZengMDPI AGEnergies1996-10732025-02-01185112610.3390/en18051126Stability Analysis and Mitigation of Thermo-Hydraulic Oscillations in Multi-Supplier District Heating SystemsPascal Friedrich0Kirill Kuroptev1Thanh Huynh2Stefan Niessen3Technology and Economics of Multimodal Energy Systems Laboratory, Technical University of Darmstadt, Landgraf-Georg-Str. 4, 64283 Darmstadt, Hessen, GermanyEnergy Information Networks & Systems Laboratory, Technical University of Darmstadt, Landgraf-Georg-Str. 4, 64283 Darmstadt, Hessen, GermanySiemens AG, Schuckerstr. 2, 91058 Erlangen, Bayern, GermanyTechnology and Economics of Multimodal Energy Systems Laboratory, Technical University of Darmstadt, Landgraf-Georg-Str. 4, 64283 Darmstadt, Hessen, GermanyIn fourth-generation district heating systems (DHSs), the supply temperature of modern heat sources such as heat pumps and waste heat can potentially be reduced by mixing in hot water from combustion-based producers, thereby increasing efficiency and facilitating integration into networks with unrenovated buildings. However, this approach introduces the risk of thermo-hydraulic oscillations driven by mixing dynamics, transport delays, and mass flow adjustments by consumers. These oscillations can increase wear and cost and may potentially lead to system failure. This study addresses the asymptotic stability of multi-supplier DHSs by combining theoretical analysis and practical validation. Through linearization and Laplace transformation, we derive the transfer function of a system with two suppliers. Using pole-zero analysis, we show that transport delay can cause instability. We identify a new control law, demonstrating that persisting oscillations depend on network temperatures and low thermal inertia and enabling stabilization through careful temperature selection, thorough choice of the slack supplier, or installation of buffer tanks. We validate our findings using dynamic simulations of a nonlinear delayed system in Modelica, highlighting the applicability of such systems to real-world DHSs. These results provide actionable insights for designing robust DHSs and mitigating challenges in multi-supplier configurations by relying on thoughtful system design rather than complex control strategies.https://www.mdpi.com/1996-1073/18/5/1126district heatingmulti-supplier systemsthermo-hydraulic oscillationsstability analysiscontrol
spellingShingle Pascal Friedrich
Kirill Kuroptev
Thanh Huynh
Stefan Niessen
Stability Analysis and Mitigation of Thermo-Hydraulic Oscillations in Multi-Supplier District Heating Systems
Energies
district heating
multi-supplier systems
thermo-hydraulic oscillations
stability analysis
control
title Stability Analysis and Mitigation of Thermo-Hydraulic Oscillations in Multi-Supplier District Heating Systems
title_full Stability Analysis and Mitigation of Thermo-Hydraulic Oscillations in Multi-Supplier District Heating Systems
title_fullStr Stability Analysis and Mitigation of Thermo-Hydraulic Oscillations in Multi-Supplier District Heating Systems
title_full_unstemmed Stability Analysis and Mitigation of Thermo-Hydraulic Oscillations in Multi-Supplier District Heating Systems
title_short Stability Analysis and Mitigation of Thermo-Hydraulic Oscillations in Multi-Supplier District Heating Systems
title_sort stability analysis and mitigation of thermo hydraulic oscillations in multi supplier district heating systems
topic district heating
multi-supplier systems
thermo-hydraulic oscillations
stability analysis
control
url https://www.mdpi.com/1996-1073/18/5/1126
work_keys_str_mv AT pascalfriedrich stabilityanalysisandmitigationofthermohydraulicoscillationsinmultisupplierdistrictheatingsystems
AT kirillkuroptev stabilityanalysisandmitigationofthermohydraulicoscillationsinmultisupplierdistrictheatingsystems
AT thanhhuynh stabilityanalysisandmitigationofthermohydraulicoscillationsinmultisupplierdistrictheatingsystems
AT stefanniessen stabilityanalysisandmitigationofthermohydraulicoscillationsinmultisupplierdistrictheatingsystems