Modelling of waste heat integration into an existing district heating network operating at different supply temperatures

Stock, Jan; Arjuna, Felix; Xhonneux, André; Müller, Dirk

doi:10.1016/j.segy.2023.100104

Cited by 14 publications

(6 citation statements)

References 30 publications

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“…Annual simulations of a small DHN with 25 HCs and decentralized prosumers were carried out using Modelica in order to evaluate different scenarios [14]. Waste heat integration was evaluated for a small DHN [15], as well as a medium-sized DHN with about 100 HCs [16]. The latter article demonstrates that dynamic simulations allow for identification of the share of waste heat that can be integrated into an existing DHN and to analyze hydraulic bottlenecks and temperature undersupply that arises from lower supply temperatures.…”

Section: Simulation Of District Heating Network: Tools and Applicationsmentioning

confidence: 99%

“…Their annual simulation of a small simple radial DHN (14 HC) takes 4 to 10 h. A simplified HC model with instantaneous heat release and a balancing valve for mass flow is described by del Hoyo Arce et al [19]. Stock et al [16] use a strongly simplified HC model for Modelica that is intended to investigate waste heat integration and supply temperature reduction in large DHNs. However, their model neglects important effects (such as pressure undersupply) and seems to be too simple (constant bypass mass flow) (see Section 2.1.1).…”

Section: Heat Consumer Modelsmentioning

confidence: 99%

“…This means that the models do not contain a fluid model that connects flow and return line, which allows for decoupling the respective equation systems for fluid flow and pressures in the supply and return line of the DHN. Stock et al [16] state that open-loop models reduce the computational effort and yield valid results when the research focus is on heat distribution and not on control of the HCs or heat sources. They successfully evaluate the hydraulic effects of the integration of a waste heat source into an existing DHN at different temperature levels.…”

Section: Aixlibmentioning

confidence: 99%

“…The novel HC model presented in this paper enriches an existing approach for simplified HC modeling (open-loop, described in [16]) with features that ensure robust and plausible behavior of the model under various operating conditions (including undesirable situations, such as excessively low supply line temperatures or differential pressures) while keeping the computational effort for simulations as low as possible. The influence of the HC model on simulation time is evaluated using this novel HC model with different configurations and simple models from two other Modelica libraries.…”

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confidence: 99%

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Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica

Zipplies,

Orozaliev,

Jordan

et al. 2024

Electronics

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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%).

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Section: Simulation Of District Heating Network: Tools and Applicationsmentioning

confidence: 99%

Section: Heat Consumer Modelsmentioning

confidence: 99%

Section: Aixlibmentioning

confidence: 99%

mentioning

confidence: 99%

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Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica

Zipplies,

Orozaliev,

Jordan

et al. 2024

Electronics

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“…Therefore, we investigate another scenario with lower supply temperatures (LT) in the district heating network of 80 to 100 • C (WH LT ). The technical feasibility of district heating operation and the sufficient heat supply to the connected consumers at these lower supply temperatures is already studied in [17].…”

Section: Studied Scenariosmentioning

confidence: 99%

Design and Operational Optimisation of a Combined Cooling, Heating and Power Plant to Enable Waste Heat Integration into an Existing District Heating Network

Stock,

Berrenberg,

Xhonneux

et al. 2023

36th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 20

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The substitution of fossil fuels in current energy systems is essential on the path to carbon neutrality. In the building sector, different renewable and waste heat sources could be used in district heating systems to replace fossil-based heating plants. However, if new heat sources are integrated into multi-energy systems, the profitability of present heating plants could decrease. At the Forschungszentrum J ülich, the waste heat from a new high-performance computer is to be integrated into the local district heating system in order to reduce overall CO 2 emissions. This waste heat integration will have an impact on the holistic multi-energy system of the campus, which is mainly supplied by a combined cooling heat and power plant (CCHP). This paper investigates the described waste heat integration using a bi-objective optimisation approach. The proposed model optimises the operation of the overall multi-energy supply system with waste heat integration. Furthermore, the optimisation model allows for the optimal design of the required heat pump system and additional absorption chiller capacity that enable efficient CCHP heat usage despite the waste heat integration. In addition, the effects of lowering district heating temperatures and changed energy prices are studied. The results show that integrating waste heat reduces the overall CO 2 emissions of the multi-energy system and even more if the integration is combined with a lowering of district heating temperatures. Furthermore, the optimisation shows that a cost reduction is feasible by increasing the absorption chiller capacity that uses the produced heat of the CCHP.

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Thermo-economic analysis and dynamic simulation of a novel layout of a renewable energy community for an existing residential district in Italy

Calise,

Cappiello,

Cimmino

et al. 2024

Energy Conversion and Management

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Modelling of waste heat integration into an existing district heating network operating at different supply temperatures

Cited by 14 publications

References 30 publications

Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica

Heat Consumer Model for Robust and Fast Simulations of District Heating Networks Using Modelica

Design and Operational Optimisation of a Combined Cooling, Heating and Power Plant to Enable Waste Heat Integration into an Existing District Heating Network

Thermo-economic analysis and dynamic simulation of a novel layout of a renewable energy community for an existing residential district in Italy

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