An adaptive double-Newton-iteration hydraulic calculation method for optimal operation of the meshed district heating network

The district heating (DH) system is one of the most efficient solutions for providing space heating with reduced energy and carbon emissions. The goal of this paper is to research the different operation control strategy of the pump, which requires addressing two issues before testing operation control strategy. One is the simulation problem, and the other is the identification problem to obtain an accurate hydraulic simulation model. In this paper, a novel adaptive double-Newton-iteration hydraulic calculation method is proposed for the meshed DH network. An identification algorithm is also proposed to obtain precise hydraulic resistances of pipelines and the coefficients of the pump curves using the measured operating data of the DH network. An optimal pressure control (OPC) strategy is then proposed to minimize the pump head based on the identified hydraulic resistances. During simulation, the hydraulic performances of DH network under the OPC strategy, the conventional constant speed control (CSC) strategy and the constant pressure difference control (CPDC) strategy were compared. Re- sults show that implementation of the OPC strategy can save about 9.0%-52.9% pumping energy compared with the CSC and CPDC strategies during the heating period.