New drives save €28,000 per year

ABB motors and variable speed drives are saving Pfizer €28,000 a year on electricity costs for chillers at its Ringaskiddy plant, County Cork.

The chillers use circulation pumps to pump heat transfer fluid to and from the cold storage tank. Pfizer asked ABB drives and motors vendor Caltech, in association with EMSA Consultants, to investigate the possibility of reducing energy use.

An energy appraisal found that the application included three 45kW motors and one 37kW motor, all of them run with soft starters. The pumps needed to maintain a flow rate of 185m3/h, but the pumps were rated for 240m3/h. To achieve optimum flow rate, gate valves were used to throttle the pumps.

EMSA, in conjunction with Pfizer Process Engineering, decided to open the valves fully and use VSDs to maintain optimum flow. They found they could achieve the desired flow rate by running the motors at 35Hz rather than 50Hz.

EMSA used ABB's Pumpsave energy saving calculation program, which predicted an energy saving of 50% per motor, with cost savings for each motor of around €7200.

Caltech's turnkey solution included high efficiency ABB EEx de IE2 motors laser aligned with the pumps.