Electricity + Control March 2019

round up ENERGY MANAGEMENT + ENVIRONMENTAL ENGINEERING

Saving energy in agri-industry

operating for 4 000 hours per year at 91% efficiency, will consume about R93 800 worth of energy, still using old- er control methods of valves that can be throttled to reduce the output of water volume and/or pressure. The same water volume and/or pressure could be achieved using a VSD to reduce the motor speed, while simultaneously further reducing the energy used, when compared to running the motor direct online from a power source. If a 10% reduction in oper-

In the agricultural sector, operating an irrigation system can be ex- pensive, with one of the primary cost factors being the cost of energy. There are ways to reduce costs and achieve savings on energy by leveraging available technology. Selecting an appropriate electric motor and variable speed drive combination can reduce owning and operating costs while provid- ing reliable performance, and WEG IE3 Top Premium Efficiency motors and WEG Variable Speed Drives (VSDs), from Zest WEG Group, can assist with this. As a supplier with a solid track record in irrigation applications, Zest WEG Group highlights an example of how energy costs can be reduced. In a pivot pump application which operates for 4 000 hours in a single year – relative to two planting cycles – it was pos- sible to do a comparison between a standard efficiency IE1 motor (91% efficiency) and a premium efficiency WEG IE3 motor. WEG IE3 Top Premium Efficiency motors offer maximum in- gress protection with a higher winding insulation system to in- crease motor life expectancy as well as efficiencies of up to 96.6%. The benefits can be seen when compared against IE1 standard efficiency motors. Using a 22 kW 2 Pole at 75% of full load IE1 motor with an efficiency of 91%, measured against a WEG IE3 motor with 93% efficiency, estimated savings amount to a cou- ple of thousand rand per year (per motor), at the current tariff. However, much higher savings can be realised by using a WEG VSD in combination with a WEG motor. An IE1 electric motor, again

The combination of higher efficiency WEG electric motors and WEG VSDs can demonstrate real reductions in energy consumption.

ational speed using the VSD is assumed, further savings of 22% to 27% could be achieved; based on the affinity law princi- ple of hydraulics. The Zest WEG Group is available for consultation on energy-sav- ing solutions for irrigation and many other industrial applications. Enquiries: ZestWEG Group Africa.Tel. +27 (0)11 723 6000, or email marketing@zestweg.com