Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica
Dynamic thermo-hydraulic simulations of district heating networks (DHN) are essential to investigate novel concepts for their sustainable design and operation. To develop solutions for a particular case study, numerous long-term simulations are required. Therefore, computational effort for simulatio...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-03-01
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| Series: | Electronics |
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| Online Access: | https://www.mdpi.com/2079-9292/13/7/1201 |
| _version_ | 1797212700534636544 |
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| author | Johannes Zipplies Janybek Orozaliev Ulrike Jordan Klaus Vajen |
| author_facet | Johannes Zipplies Janybek Orozaliev Ulrike Jordan Klaus Vajen |
| author_sort | Johannes Zipplies |
| collection | DOAJ |
| description | Dynamic thermo-hydraulic simulations of district heating networks (DHN) are essential to investigate novel concepts for their sustainable design and operation. To develop solutions for a particular case study, numerous long-term simulations are required. Therefore, computational effort for simulation is critical. Heat consumers (HC) are numerous and determine the dynamics of mass flows and return temperatures in the DHN. Thus, the way in which HCs are modeled has significant impact on the computational effort and the results of the simulation. This article presents a novel Modelica-based model for HCs that builds on an existing simplified modeling approach (open-loop design). The calculation of mass flow and return temperature is improved in terms of robustness, plausible behavior and low computational effort. In particular, the model reacts to limited differential pressure and supply temperatures to ensure plausible behavior across all operating conditions, including undersupply situations. The model is successfully tested using an exemplary DHN. The analysis proves that the HC model itself requires little time to simulate. Nevertheless, it significantly influences the simulation time for the entire DHN, which varies by a factor of five for the investigated system depending on the HC model. Fast dynamics, including a bypass in the model and correction of deviations between set point and actual heat load increase the simulation time, so users should sensibly choose how to use these options. HC models triggering many state events result in high computational effort. Compared to other simple HC models, the proposed model produces more plausible results while maintaining at least equal simulation performance (for models without bypass) or even improving it (for models with bypass, CPU time is reduced by at least 35%). |
| first_indexed | 2024-04-24T10:46:33Z |
| format | Article |
| id | doaj.art-573190df1ddb4e78b715b96bd4654e88 |
| institution | Directory Open Access Journal |
| issn | 2079-9292 |
| language | English |
| last_indexed | 2024-04-24T10:46:33Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Electronics |
| spelling | doaj.art-573190df1ddb4e78b715b96bd4654e882024-04-12T13:17:03ZengMDPI AGElectronics2079-92922024-03-01137120110.3390/electronics13071201Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using ModelicaJohannes Zipplies0Janybek Orozaliev1Ulrike Jordan2Klaus Vajen3University of Kassel, Institute of Thermal Engineering, Department of Solar and Systems Engineering, Kurt-Wolters-Str. 3, 34125 Kassel, GermanyUniversity of Kassel, Institute of Thermal Engineering, Department of Solar and Systems Engineering, Kurt-Wolters-Str. 3, 34125 Kassel, GermanyUniversity of Kassel, Institute of Thermal Engineering, Department of Solar and Systems Engineering, Kurt-Wolters-Str. 3, 34125 Kassel, GermanyUniversity of Kassel, Institute of Thermal Engineering, Department of Solar and Systems Engineering, Kurt-Wolters-Str. 3, 34125 Kassel, GermanyDynamic thermo-hydraulic simulations of district heating networks (DHN) are essential to investigate novel concepts for their sustainable design and operation. To develop solutions for a particular case study, numerous long-term simulations are required. Therefore, computational effort for simulation is critical. Heat consumers (HC) are numerous and determine the dynamics of mass flows and return temperatures in the DHN. Thus, the way in which HCs are modeled has significant impact on the computational effort and the results of the simulation. This article presents a novel Modelica-based model for HCs that builds on an existing simplified modeling approach (open-loop design). The calculation of mass flow and return temperature is improved in terms of robustness, plausible behavior and low computational effort. In particular, the model reacts to limited differential pressure and supply temperatures to ensure plausible behavior across all operating conditions, including undersupply situations. The model is successfully tested using an exemplary DHN. The analysis proves that the HC model itself requires little time to simulate. Nevertheless, it significantly influences the simulation time for the entire DHN, which varies by a factor of five for the investigated system depending on the HC model. Fast dynamics, including a bypass in the model and correction of deviations between set point and actual heat load increase the simulation time, so users should sensibly choose how to use these options. HC models triggering many state events result in high computational effort. Compared to other simple HC models, the proposed model produces more plausible results while maintaining at least equal simulation performance (for models without bypass) or even improving it (for models with bypass, CPU time is reduced by at least 35%).https://www.mdpi.com/2079-9292/13/7/1201modelicadistrict heating networkheat consumersimulation performance |
| spellingShingle | Johannes Zipplies Janybek Orozaliev Ulrike Jordan Klaus Vajen Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica Electronics modelica district heating network heat consumer simulation performance |
| title | Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica |
| title_full | Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica |
| title_fullStr | Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica |
| title_full_unstemmed | Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica |
| title_short | Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica |
| title_sort | heat consumer model for robust and fast simulations of district heating networks using modelica |
| topic | modelica district heating network heat consumer simulation performance |
| url | https://www.mdpi.com/2079-9292/13/7/1201 |
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