Hydraulic resistance identification and optimal pressure control of district heating network

Hydraulic performance of district heating (DH) network is the key to energy reduction of DH system. Efficient hydraulic operation strategy requires precise values of the hydraulic resistances of pipelines. In this paper, a hydraulic resistance identification method was developed. With this method, precise hydraulic resistances of all the pipelines in the DH network can be obtained based on the pressure and flow rate values observed at the heating substations under different hydraulic conditions. An optimal pressure control strategy of DH network was established based on the identified hydraulic resistances for energy reduction of the pumping systems. The feasibility and effectiveness of the hydraulic resistance identification method were analyzed with the well-developed hydraulic simulation technique of district heating network realized in Matlab environment. Hydraulic performances of the optimal pressure control (OPC) strategy were compared with the traditional constant pressure difference control (CPDC) strategy. Results show that the pumping energy of DH system under the control of CPDC can be reduced by 14.6% compared with OPC during the heating period.