Reducing the energy cost of indoor commercial irrigation.

A farm irrigation systems was a good example of how investing in new systems improves performance and saves money not only in large industrial operations but also in smaller installations.

Rising electricity cost

As an example, Riecor, a South African customer in the farming industry was struggling with the continuously increasing electricity prices. As the South African economy developed over the past five years or so, growing demand for electricity has meant that rates rose by more than 20% every year.

Since the electricity costs of running motors and pumps in irrigation systems was one of the company’s biggest operating expenses profitability was hit. The customer’s old irrigation system was based on a piping network that included numerous water pumps running at constant speed, with control of the flow rate and destination done by the manual opening and closing of valves in the pipelines. The system worked, but was inefficient.

In addition, the need to manually open and close the valves depending on water demand, combined with the hassle of frequent power outages and voltage dips from the electrical utility, made the whole process very labour intensive. Restarting motors had become almost a full-time job as the labour needed to start one of the farm’s six pumping stations could take one person up to an hour, and sometimes there were as many as three power outages in a day.

NEW DRIVES-OLD PUMPS

When the farm management began seeking alternatives, ABB South Africa’s energy efficiency engineers proposed a solution where six general purpose drives were installed at the water pumps at one of the farm’s six pumping stations. Five of the VSDs to run irrigation pumps with 45-75kW motors, and the sixth used on the water transfer pump.

With the new VSD units installed, Riecor saw a big drop in electric energy use. Demand from the irrigation system was reduced by 116 kW, equalling an impressive 40% drop in electric consumption at just one pumping station. In financial terms, the 2,970 hours that irrigation pumps operate per year equates to an annual savings of nearly £16,000 in electricity costs. The payback time amounted to a short 7 months. In addition, productivity improved as operators now only needed to flick a switch to restart the entire system.

REDUCED WEAR AND TEAR

Maintenance was reduced as the drives’ long ramp-up time that allowed smooth pipe-filling, so the previous mechanical stresses on the pump couplings during start-up were eliminated. In addition, there are reduced friction losses in the pipes, water hammering has disappeared, and less wear and tear has been seen on the impeller due to the extended ramp-up and ramp-down times.

Any process that is using pumps and fans driven by motors can achieve important monetary savings and operational benefits with the use of VSDs. ABB’s EnergySave calculator helps estimate how much energy users can save in applications such as pumps, fans and compressors.

Learn more about our customers benefiting from ABB energy efficiency here.

Save money buying ABB  energy saving drives from 999 Inverters