The Value of Fault Detection and MBCx For Chillers

We are always asked "What can I save by installing Fault Detection Software or starting a Monitoring Based Commissioning" program. This has a million "It depends" answers. I thought it worthwhile to share some specific findings that we have learned with chillers.

We have been fortunate to have the opportunity to work with Banner Health on a multi-year effort to install ClimaCheck on 73 chillers and continuously monitor their performance. ClimaCheck is an advanced refrigeration system analytics platform. The chillers range in size from 300 tons to 1450 tons and are all water-cooled centrifugal. The vast majority have VFDs.

The graph above shows a chiller that had its variable geometry diffuser actuator repaired with a resulting 40% improvement in efficiency.

• In the last 6 months alone, 24 issues have arisen that typically reduce chiller efficiency by 10% to 15%. However, some issues have impacted efficiency by as much as 40%.
• Issues have included low refrigerant levels, refrigerant level control problems, inlet guide vane actuator problems, variable geometry diffuser problems, surge maps needing to be reset, fouled condenser tubes, and low flow through condensers.
• Several of the chillers with low refrigerant had been repaired 3 years ago but lost enough refrigerant to lose 15% efficiency.
• The corrections to these chillers are delivering over $130,000/year in electricity.
• All of the repairs improve the reliability of these chillers. For example, chillers that are low on refrigerant will run at a higher lift. The increased lift will result in surge during summer operation. Either the chillers will undergo massive vibrations during surge or shut themselves down at a time when you need them the most.

We were originally shocked at the number of issues. However, further thought made us realize that chillers are machines with lots of mechanical components. These chillers run with constantly changing conditions (loads, flows, temperatures) so it is only reasonable for issues to constantly arise. It is shocking that our industry doesn't invest the appropriate resources to keep these mission critical machines running not just efficiently but also reliably.

I would love to hear others' thoughts on what they are finding through continuous monitoring of facilities so we can push our industry into the current generation of monitoring and analytics that other industries have already entered.