Computer simulation and full-scale measurements of the load flow in a functioning heating network

Abstract

The article aims to identify patterns in the distribution of heating energy to consumers with a varying availability of regulation equipment under real conditions of a central heating network, as well as to compare the results of computer simulation with full-scale measurements. For computer simulation, well-known mathematical methods for calculating the load flow in hydraulic circuits were used. Experimental studies of the operation modes of heat supply systems were carried out using the data of the control and monitoring systems of thermal power plants using the Siemens Simatic PCS7 software, a Portaflow 300 ultrasonic flow meter, stationary electromagnetic flow transducers, verified and certified manometers and thermometers. The graphs of the actual hydrodynamic modes of the heating network under study were obtained at outdoor air temperatures from +8 to -37°C, as well as under abnormal conditions (temperature drop in the supply pipeline and pressure drop at the heating network input). It was proposed to use jointly the simulation by means of the JA_Net software and full-scale measurements of the thermohydraulic operating modes of a centralised heat supply system, whose consumers have a various degree of regulation equipment. It was shown that the proposed complex method of qualitative and quantitative assessment of the efficiency of district heating networks makes it possible to identify the features of control of their hydraulic modes when connecting new consumers with a varying degree of automation. According to the obtained characteristics of changes in the flow rate of the coolant in the consumers’ internal systems depending on the pressure drop at the tie-in point, the lack of response to emergency situations on part of the consumers whose heat supply systems are equipped with the means of qualitative and quantitative regulation of the heat load, is associated with the process of automatic adjustment of the degree of opening of flow controllers and control valves at individual points. In future work, we will develop guidelines for levelling the imbalance of the heating network under the conditions of uneven provision of facilities with automation equipment when implementing projects for the complex modernisation of heat consumers or connecting new facilities to existing heat supply networks.