MODERNIZATION OF THE ELECTRIC DRIVE OF PUMPING UNITS OF THE DISTRICT HEATING NETWORK IN THE CONTEXT OF INCREASING THEIR ENERGY EFFICIENCY

Abstract

Quantitative and qualitative indicators of the modernization of the electric drive of a pumping unit of a network with throttle control of the coolant supply of a centralized heat supply system are determined. The possibility of modernizing the electric drive by replacing outdated electric motors of energy efficiency class IE1, which are still used in electric drives of pumping units, with electric motors of energy efficiency classes IE2 and IE3 from different manufacturers, has been substantiated. The energy consumption was calculated based on the technical data of the pump and electric motors provided by the manufacturers and includes the calculation of the energy consumption of pumping units in a typical operating cycle typical for district heating networks, which involves operation at reduced load for a long time. Comparative calculated data on the daily and annual energy consumption of the considered electric motors in a typical operating cycle of a pumping unit, with respect to the least energy-efficient electric motor among those considered, were obtained. The practical significance of the results obtained is to understand that the selection of an electric motor by efficiency at variable load, i.e., actually on the basis of the IE energy efficiency class assigned in accordance with the IEC 60034-30-1 standard, is incorrect, It is substantiated that the choice should be made using the efficiency interpolated by the method of polynomial interpolation of the motor loss curve, while taking into account the economic feasibility of choosing an electric motor between energy efficiency classes, in this case IE2 and IE3, and different manufacturers.