When people ask me what I do for work, I generally tell them I’m a building systems engineer, with a big focus on making facilities more energy efficient and comfortable for occupants. One common task entails going on a building site visit to perform an energy audit or assessment. During these visits, we walk the site, inventory all energy-related equipment (including lighting, mechanical systems, building envelope, etc.) and speak with the building operator about how they run the building and any issues or concerns they have regarding maintenance, equipment that is not working properly, or comfort problems. The end result is typically a report documenting the existing building systems, with recommendations on equipment upgrades or operational changes that can be made to save energy or improve comfort. We also will provide quantification of energy and cost savings for each identified opportunity.
24/7 Operation - Low Hanging Fruit?
At this point in the conversation, people will sometimes ask what our most frequent recommendations are and where the biggest potential for energy savings is usually found. Folks are often surprised to learn that one of the most common opportunities we identify is equipment running continuously 24/7, even in buildings such as offices or schools where the actual occupied hours are far lower. Depending on the size of the uncontrolled equipment, reducing operating hours to more closely match actual occupancy patterns can lead to a significant reduction in energy use. Turning off equipment when it’s not needed may not have the same visible cachet as installing solar panels, but can be a very cost effective way to achieve more efficient operation.
Not Always So Easy
Image by Flickr user Steve Lee
But why is this such a common finding? Isn’t it obvious that equipment should be turned off (or at least turned down) when it’s not needed? On one level, operating a building in “24/7 mode” is completely understandable. After all, the main priority of facilities staff is to keep the building running effectively and to keep building occupants happy and comfortable. They often need to accomplish this using limited time and resources, and are not always able to think about energy impacts. Sometimes the easiest way to meet these objectives is to leave everything running overnight, so that they don’t have to worry about whether the building will be warm (or cool) enough when people start coming in the next morning. Or perhaps the facilities staff will implement a quick fix to address an occupant complaint in lieu of diagnosing the root cause of a problem. Most of the time these quick fixes bypass the automatic control of the systems in the building. Over time, a building’s efficiency can suffer death by a thousand cuts as these quick fixes build up and the underlying problems go unresolved.
Conservative, Gradual Fixes
Image by Flickr user b k
These kinds of issues are easy to identify, and the remedies typically don’t require investing in expensive capital improvements or even implementing new and complex control sequences. However, it is not always so simple to get the necessary changes implemented. Building operators tend to be conservative and are reluctant to make any operational changes if things have been working fine the way they are (that is to say, they’re not receiving occupant complaints and are free to work on their scheduled regular maintenance). Before making any recommendations, it is necessary to listen closely to the facility manager’s concerns and take the time to address any questions that come up. Sometimes a gradual approach can work. For example, if the air handling units are currently operating 24/7 with no setback for space temperature setpoints, one recommendation could be to add a setback of just 2°F or so for unoccupied periods. If after a couple of weeks things seem to be working fine, the setback can be increased and the process repeated until a good balance is found.
Staff Commitment Required
It is important to note that any change that is made requires the complete buy-in and understanding of all the facilities staff. Otherwise, after the first comfort complaint (even if the reason has nothing to do with the changes that were made) things may revert back to how they were operating previously. Training maintenance staff to not just put out the fire, but also to find out what caused it and treat the problem at the source, is essential in achieving long term and consistent energy savings. In a future post, I plan to explore the various incentives that are available to facilities engineers for reducing energy use in their buildings. Building operators understand the buildings in which they work better than anyone else ever will, and they are a vital boots-on-the-ground resource for any successful energy management initiative.