Operational optimization of district heating systems with temperature limited sources

Journal Article (2020)
Author(s)

Sam van der Zwan (Deltares)

I.W.M. Pothof (Deltares, TU Delft - Support Process and Energy)

Research Group
Support Process and Energy
Copyright
© 2020 Sam van der Zwan, I.W.M. Pothof
DOI related publication
https://doi.org/10.1016/j.enbuild.2020.110347
More Info
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Publication Year
2020
Language
English
Copyright
© 2020 Sam van der Zwan, I.W.M. Pothof
Research Group
Support Process and Energy
Volume number
226
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Abstract

Future district heating systems (DHS) will be supplied by renewable sources, most of which are limited in temperature and flow rate. Therefore, operational optimization of DHS is required to maximize the use of renewable sources and minimize (fossil) peak loads. In this paper, we present a robust and fast model-predictive control approach to use the thermal mass of buildings as a daily storage without violating temperature constraints. The novelty of this paper includes two elements. First, the focus on an operational control strategy that explicitly accounts for temperature-limited renewable sources, like a geothermal source. Secondly, the optimization problem is formulated as a (nearly) convex optimization problem, which is required for adoption of model-predictive control in practice. The examples show that the peak heating demand can be reduced by 50%, if the thermal inertia of the buildings is used and the heating setpoints are adapted. Furthermore, the operational optimization finds the proper balance between benefits of pre-heating using renewable sources with limited capacity and costs of additional heat losses due to pre-heating.