John Guthrie, Energy Efficiency Manager ABB, writes: It always pays to keep a sharp eye out – you just never know when an opportunity to save money might come along. An unexpected sale of something you’ve wanted for a long time. A discount off something you always buy anyway. Or a chance to cut your energy bill.
That was just what an engineer at ABB authorised value provider, MKE, saw recently when installing some electrical panels at Kent-based Tenterden Leisure Centre. Used to spotting money saving opportunities, the engineer realised that the air-handling unit (AHU) at the leisure centre was ideal.
Like many such applications, the AHU’s motors were run direct on line - two-speed motors were operating at either 22 kW or 4 kW, controlled by humidity and temperature sensors through a building management system. The motors had to run at the different speeds many times during opening hours.
MKE advised the leisure centre that they could achieve substantial savings by using ABB variable-speed drives (VSDs) to run the motors.
When one of the motors failed in the AHU, the leisure centre decided to replace both motors and go for the VSD option.
MKE replaced the motors with two ABB standard induction motors, each driven by a 22 kW ABB HVAC drive. The VSDs signal the motors to start, running them at 40 Hz for the high speed during the day and 20-15 Hz for the low speed at night.
But the savings potential didn’t stop there – another project installed three 12 kW ABB drives on the pool pump system.
The pool has three pumps and previously two ran on duty, one off. With the new VSDs, all three pumps run together at a reduced speed. This saves a massive 25 percent off the pumping system’s electrical consumption.
Together with a refurbished drive train for the AHU, the projects at the leisure centre are saving up to 20 percent on energy costs.
MKE estimated an 18 months payback but Tenterden Leisure Trust has achieved that in just over a year since the drives were installed.
It certainly pays to keep an eye out for energy savings – ABB and its partners can help you discover the savings potential at your facility with their energy assessments. See here for more details.