Evaluating Network Storage Effects in District Heating Scheduling through Coupled Simulation and Optimization

A new method for scheduling heat generation in district heating networks was developed that exploits the flexibility potential of district heating networks. The flexibility considered includes the heat storage capacity of the district heating network itself, which results from decoupling the heat supply into the network from the current consumption. For this novel method, conventional operational planning using a mixedinteger optimization model was coupled with a thermohydraulic simulation of the district heating network. This allows the physical and thermohydraulic properties of the grid to be taken into account while ensuring minimal operating cost and CO2 emissions. A distinguishing feature of the proposed approach is its capability to enable tool coupling while preserving the underlying models already existing largely in their original state. This paper describes how optimization and simulation are coupled, which data is exchanged between the subsystems, and how this allows the flexibility of the district heating network to be exploited. In addition, this new method of scheduling is tested on a real use case with historical data to analyze the real benefit. The results of the real use case are presented and reveal that the operating cost can be reduced. Both individual characteristic days and an entire year are considered.