A Coupled Hydraulic Balance Operation Method for District Heating Networks to Improve Flexibility of Multi-Energy Systems

The district heating networks (DHN), an important component of multi-energy systems. Its natural passive heat storage characteristics can provide flexibility for the power grid and promote the consumption of renewable energy connected to the grid. Currently, most of flexibility improving method using DHN's thermal storage haven't considered the hydraulic balance of the complex topology networks, and directly sets the flow rate of each pipe. This leading to that the flexibility improving method may not take effects in practical application since the hydraulic balance may not be satisfied. This paper proposed a pipe network coupled flow regulation method to improve the flexibility of district heating networks. A hydraulic balance model corresponding to the resistance coefficients of all pipelines of the pipe network is proposed, and the simulation accuracy of flow rate for main and branch road under different pressure drops is verified experimentally. The relationship between pipe resistance coefficient, pump work and flow distribution in the final topology pipe network when the flexibility of the district heating networks is enhanced by flow regulation is obtained. This method can realize hydraulic balance regulation when DHN flow regulation is used to provide flexibility for power system.