Making Music with Your HVAC Systems
Ensure your operations and maintenance departments are cared for and in tune.
In these days of COVID-19 uncertainty, everyone in the industry is scrambling to make our buildings as safe as possible for their occupants. The greatest pressure is on the operations and maintenance (O&M) personnel responsible for each building. This is a current issue that needs immediate attention, but O&M responsibilities are really no different than they have always been.
The most effective O&M is actually maintenance, operation, and optimization (MO&O). I like to think of building systems MO&O as an orchestra.
Maintenance is analogous to caring for and tuning the instruments. Those instruments will not have a prayer of making music if they are not properly stored, handled, and maintained. This is true for pumps, fans, chillers, cooling towers, boilers, heat exchangers, control system devices, etc., in buildings. In addition, the musicians will not be able to successfully play together unless the instruments are tuned, similar to an HVAC system needing all of its sensors calibrated.
Once the instruments are ready, they can all be played individually for solos, but that is not an orchestra. An orchestra is when all of the instruments play together under the direction of a conductor. Many HVAC systems, including manufactured equipment, such as rooftop units, boilers, and chillers, are engineered collections of components designed to work together under the direction of a control system.
Building systems operation is making sure all of the components are communicating with and reacting to each other as intended. When an orchestra conductor is successful, it results in beautiful music. If the musicians are not paying attention, are unprepared, or have not cared for their instruments, the dissonant results can be heard by all.
With HVAC systems, it’s not always so obvious when components are not performing well together. Sometimes, occupants recognize it right away due to uncomfortable temperatures, unpleasant odors, doors that are difficult to open, wind tunnel-like airflows through doors or hallways, etc. However, many chronic system-level deficiencies may go unnoticed by occupants. If the O&M staff are not paying attention to the subtleties of system operation and integration, deficiencies may fester for an extended period of time.
Those are the types of issues typically uncovered and, hopefully, addressed through retro-commissioning. However, if the building owner has the resources, it would be best for the O&M staff to have the time and skill set to evaluate system operation on a regular basis. If the facility has a central building automation system (BAS), operation checks could be performed daily with a well-designed user interface. Without a BAS, the O&M staff will likely need customized procedures, training, and tools for confirming the systems are operating as intended. These more time-intensive manual checks would more realistically be performed on a quarterly or annual basis.
The final piece of the MO&O process is optimization. An orchestra does not generate its best music the first time it plays through a new piece. It requires many practice sessions and hard work to figure out how they can create the desired sound and experience on a consistent basis. The same is true for building systems.
Even if it is commissioned at the end of construction to confirm as-designed performance, the initial operation should never be expected to be the best and most efficient performance an HVAC system can deliver. By definition, HVAC systems are designed for worst-case operational scenarios, i.e., maximum number of people, maximum number of occupied hours, etc. Very few buildings actually reach those levels of occupancy and use; however, some actually over-use their original intent, but that’s another story.
After initial turnover and training, the O&M staff should understand enough about the design intent to determine whether the building is occupied and used as expected by the designers. If not, building operators may be able to optimize the system by adjusting minimum outside air set points, adjusting variable water and air system pressure set points, resetting supply air and/or water temperature set points, etc., as appropriate to maintain safe and healthy working conditions as efficiently as possible.
This optimization process should be incorporated into the O&M staff job description as time and skill set permit. If it is impractical with in-house O&M staff, I recommend the building owner consider outsourcing periodic system optimization reviews and adjustments, including O&M staff training to sustain optimal system performance between reviews.