engleski

POSITIVE EFFECTS OF VARIABLE FREQUENCY DRIVEN PUMP

Energy efficiency of the water pipeline system is analysed on the physical model of the water supply system through the application of the pump with nominal characteristics (unregulated pump) and the same pump controlled by variable frequency drive (frequency regulation). The functional advantage of pump frequency regulation is quantified in terms of reducing water loss due to leakage through the circular orifice (crack/opening). The occurrence of leakage was simulated by opening a 20 [mm] diameter circular orifice drilled through the pipe wall (polyethylene pipe (PE), 110/90 [mm]). The influence of pressure change on the leakage outflow in the physical model was also investigated in order to find the leakage exponent N1 in the ratio Qi / Q1 = (hi / h1) N1 where Q and h represent the leakage flow and the corresponding pressure head. The results of the research showed that frequency regulation of the pump enables an average reduction of energy consumption by 16.5% in the case of water demand pattern characteristic for a larger agglomeration (city), or by 41.5% in the case of a smaller agglomeration. Furthermore, exponent N1 receives a value of  0.5, indicating only a minor influence of the elastic deformations of the pipe material in the regime of the tested pressure head range (20 - 70 [m]).

pump frequency control, intensity of leakage, water pipeline system, physical model, numerical model, pressure and flow measurements

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