• Jack Rind

Leveraging FDD to Improve IAQ, Generate Energy Savings, and Secure Utility Rebates

Stakeholders are being challenged with balancing a plethora of constraints such as: thermal comfort guidelines, energy management, occupant health and safety requirements, equipment maintenance, and efficient facilities management. Without some type of continuous feedback on building automation system (BAS) data within a facility to identify actionable insights, it is not possible to monitor the impacts of operational changes or effectively handle equipment anomalies. That is where Fault Detection and Diagnostic (FDD) software should be leveraged to provide continuous commissioning of a BAS. FDD helps ensure buildings’ goals of improving indoor air quality (IAQ), increasing the efficiency of property teams, and helping to generate revenue.

The first step in improving building IAQ is making sure the relevant metrics are being tracked and monitored such as Carbon Dioxide (CO2), relative humidity, temperature, and volatile organic compounds. At a minimum, facility teams need to understand when these metrics deviate from their optimal ranges. FDD can then be used to provide more advanced alerting around building operations that may be adversely impacting these metrics, such as clogged filters in ducts that need replacement, which are surfaced by pressure alarms. Moreover, dampers failing to open or close properly often cause variances in air flow versus the desired setpoints, as well as static pressure issues. Another example would be tracking building pressurization to ensure that outside air infiltration is not occurring and that spaces are receiving the minimum required ventilation of fresh air.

Another benefit to using FDD software is its impact on increasing the efficiency of facility teams; FDD helps facility teams to become proactive instead of just reactive. Rather than waiting for equipment to outright fail or for monthly preventive maintenance to surface an issue, FDD software uses logic to highlight a piece of equipment as it begins to enter an anomalous state. An example could be a vibration sensor on a rotating piece of equipment— as more vibrations are measured this is a sign of a possible crack and that a replacement is needed.

Understanding that a key component of FDD is the prioritization of alerts to create actionable information is an important element of its adoption. Logic can be coded in the FDD software to classify anomalies by severity, then these are reported to facility teams in a distilled list. A building team needs to know when an air handling unit supplying a whole floor has an issue versus a VAV box that serves one room. And too many alerts flooding a building engineer’s mailbox can be just as problematic as receiving no alerts at all. Furthermore, FDD is used to implement more advanced HVAC control strategies that lead to energy savings and ultimately facilitate the activities needed to qualify for utility rebates. A few of these strategies proven to drive energy savings are as follows. Whether it be enthalpy-based, which considers the moisture in the air as well as the heat content in terms of temperature, or solely based on outside air temperature, efficient economization helps to maximize the amount of free cooling in milder weather.

Another strategy is using demand-controlled ventilation by monitoring the CO2 in a space like a conference room to reduce the runtime of the equipment in that zone through periods of vacancy Additionally, FDD can be used to implement automatic supply air temperature and chilled water temperature resets; increasing the supply temperature setpoints in milder weather can help reduce the lift on compressors, in turn saving energy. I¬n all these strategies, FDD can track the BAS point data and help to both verify and ensure these energy conservation measures (ECMs) remain implemented. Reports detailing these ECMs can then be packaged and provided to a utility provider as part of a rebate program.

Low-cost measures, as described within, were implemented at one of InSite’s client facilities comprising a complex of three office buildings covering a total of 331k square feet. InSite received an $85k rebate as part of a building tune-up program by submitting ECMs with an annualized value of $15k. The submission was completed in a phased approach through benchmarking and auditing, identification of opportunities, opportunity implementation, and opportunity verification.

In conclusion, for a facility team to make use of disparate data streams, software like FDD must effectively aggregate and process the data and has been proven to support utility rebate qualification. The FDD software should be used to apply engineering principles and analysis to develop meaningful insights for process improvements, facility optimization, and as a revenue generator.

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