SUBSTANTIATION OF ENERGY EFFICIENT WATER SUPPLY IN CLOSED IRRIGATION SYSTEMS
Relevance of research. The research is aimed at improving the energy efficiency of automated water supply in irrigation systems. The purpose and objectives of research. The purpose of the research is to reduce the specific energy consumption for pumping water by pumping stations (PS) in closed irrigation systems (CIS). The task is to substantiate the efficiency of the method of automated control of water supply to the CIS when regulating the pressure at the outlet of the pumping station, which is set by the sum of hydraulic losses in the network from the pumping station to irrigation equipment (IE), static and free pressure at the dictating hydrant of CIS. The logical-mathematical model and technological conditions of energy-efficient water supply management "when it need" in CIS are given. The technical requirements for pumping units (PU) and auxiliary technological equipment of PS are presented in the application of automated water supply control with the use of frequency converters (FC).Research methods: experimental, mathematical modeling. Substantiation of the feasibility of introduction of automated electric drive with FC, as one of the measures of energy efficiency improvement, was carried out based on the results of energy audits of the PU and the CIS with the use of measuring equipment on the request of inter-district water management administration. The object of the energy audit is the CIS, which has been in operation since 1979. The PS is equipped with four PU with centrifugal section pumps 150-CVE-350-23/3 (D = 350 mm) and drive motors of the brand MAF315SK-4 with a rated power of 132 kW. During the period of operation the reconstruction and restoration of the CIS took place. “Dnepr” sprinkling machines have been replaced by modern low pressure SM and drip irrigation systems. With the replacement of irrigation equipment, asbestos-cement field pipelines with diameters D = 400 mm were replaced too with the plastic ones of D = 200 mm. The configuration, hydraulic characteristics of the CIS and modes of operation of the PU were changed. The efficiency of the pumps 150-CVE-350-23/3 decreased by 10-15% during the long-term operation of the PU. Research results. For energy efficient water supply management, it is proposed to: replace four worn pumps 150-CVE-350-23/3 with three pumps of domestic production ЦН400-105б; implement a system of automated water supply management at the CIS with the use of FC. Conclusions. The effectiveness of the application of a new method of water supply control in the CIS, which provides for automatic control of the pressure at the outlet of the PS, is given by the sum of hydraulic losses in the network from the PS to the IE, static and free pressure at the dictating inlet of the operating IE, using the proven FC. Introduction of automated electric drive with the FC on the PS-4 of the “Repin” CIS enables to reduce the daily power consumption from 12% to 25%.
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