January 16, 2018
This month’s blog post details how I approach an already high performing building and how you can look at your building with fresh eyes.
Luckily I get to work with facility owners who have done all the “easy” stuff and have a high performing building. These are the buildings I like to work with, they are more of a challenge and the owners and operators are really excited about the energy savings I’ve found whether it’s through a retro-commissioning project or the building is part of our energyPLAN service.
There are two main challenges with a high performance building: (1) maintaining that high performance and (2) continual improvement. The starting point for both is using the building automation system to collect data on how the building is performing.
Maintaining your high performance is relatively simple, the common 80/20 rule is applicable here. For 20% of the effort 80% of the savings can be maintained. As long as your main equipment is operating correctly, resets are functioning, and schedules are relatively correct that is 80% of the potential savings. Staff can perform quarterly reviews of those key items or monitoring based commissioning tools can be used.
Continual improvement requires data as well to realize even greater savings on an already energy efficient building. In addition to data, a fresh set of eyes is recommended. The biggest obstacle I often encounter is the mindset that an ENERGY STAR score of 92 means there is little to no potential left. When I look at that number it’s a good place to start but by no means dictates the final savings you’re able to achieve. The limitation of an ENERGY STAR score is that it’s a statistical comparison with other similar buildings, however it doesn’t indicate what the potential performance is.
So how do you find that additional improvement in your building? Your building may look the same from the outside as it did 5 years ago, but its operating characteristics are always changing and always evolving. Those changes allow opportunities to further refine operation.
For example, in a recent project a chilled water reset was implemented when the building was opened and has worked well with no issues. Since opening the building has received lighting upgrades which greatly reduce the space cooling load. Now the chilled water reset can be expanded. Or a data center has been expanded requiring significantly more chilled water, now its economically feasible to install a fluid cooler for free cooling in the winter.
A lot of the opportunities I find are just simply hang-ons from the original construction or the last building engineer. The ‘that’s how it’s always been’ mentality is pervasive. The other source of opportunities is often when a strategy was tried and failed either because it was implemented incorrectly or it was overwhelming for the staff to control. Both of these issues can be resolved with experienced personnel. Often times the greatest benefit I bring to a building staff is experience implementing strategies at dozens of other buildings in the last couple of months. Seeing and implementing dozens of different methods for the same strategies allows me to bring fresh options and help identify the best method for a specific situation.
Unfortunately building engineers do not always get the benefit of that increased exposure, so seeing how multiple buildings are running the same reset is incredibly helpful.
The other source for continual improvement is answering operational questions the engineer may have. Often times the engineer spends their time putting out fires and they aren’t able to spend the time on questions regarding efficient operation. A couple of examples: is it better to use operate two smaller chillers or one larger machine or which is more important, supply air temperature reset or chilled water reset. Getting an energy expert in to test and solve these types of questions is a great opportunity to further refine operations.
There is a significant amount of potential in existing high performing buildings whether they were built 5 years ago or 100. Typically we see savings in the 5% range for an already high performing building. Identifying the additional savings available in your building may take some outside help but good help will ensure those savings are maintained and will extend your staff’s skill set.