Research on energy-saving strategies for parallel pumps in closed circulating water systems

The least square method is used to fit the operating condition curve and characteristic curve of the water pump.Aiming at the low efficiency problem that occurs when water pumps of the same type are operated in parallel under low flow conditions or during add/subtract pump switching,a solution using pump units of large,medium and small different types is proposed.Aiming to minimize the sum of power consumption of the parallel pump group,the optimal scheduling model of the pump group is established.Flow rate,head,speed ratio and high efficiency zone are set as constraint conditions,and the energy-saving scheme for the pump group is solved using the dung beetle optimization algorithm.Practical verification shows that in a typical closed circulating water system,under the condition that the full load cooling capacity of the water chiller is 6 200 kW,the operating flow of the water pump group is from 102 m3/h to 1 020 m3/h.Different types of parallel pump groups with large,medium and small pump combinations are compared with the conventional parallel pump groups of the same type,the comprehensive efficiency of the pump group is increased by 5% to 10% in the 10% to 40% load section,the annual power saving is 5 370 kW·h,and the annual power saving rate is 5.3%.