THE BENEFITS OF CLOSED LOOP CONTROL ON INVERTERS

A trio of our talented engineers, Colin, Michael & Gordon recently installed twenty-four ABB ACH580 inverters at a university. But what they found during the installation amazed them...

The drives were being fitted to control a combination of AHU’s, chiller pumps and swimming pool circulation pumps.

The applications were commissioned in ‘closed loop control’ to maximise energy savings, with the AHU drives controlling on duct pressure to deliver constant flow, regardless of filter condition. ABB’s ACH580 units give an alarm at full speed to indicate that filters are to be replaced.

Following the installation the energy reduction actually exceeded that predicted and now equals 230,744 kWh. Our picture above shows the before & after energy consumption of one of the AHU's—based on a clean filter.

The chiller pumps use return water temperature for closed loop control. So far, so good.

But what stunned our expert engineers during the installation? Well, they noticed that a non-ABB affiliated company had fitted drives (by another manufacturer) to a number of the larger AHU’s on site. This work had been carried out approximately 5 years ago. However, the drives had been allowed  to run at full speed with no control loop connected. The result for our customer: zero energy savings. On being advised of this the university’s facilities management team asked EDC to quote for sensors and recommissioning of the inverters to remedy the problem. Payback? It’ll be a matter of weeks as the major part of the investment has already been made.

And the moral of this story: experts make a difference. This university invited an ABB Authorized value provider of drives, to fit its inverters and maximise energy savings. It called on the skills of EDC whose engineers are trained to the highest ABB standards. As a result, they not only got a quality product and service, they also discovered that more energy savings could be made. Savvy energy savings made easy. As easy as EDC.