From OC Atlanta Issue 1-11
When people describe buildings as “high performance,” what they are actually talking about is energy efficiency. The systems of a high-performing building require less energy to produce a comfortable end-user environment compared to the energy required by low-performing systems. The result, in addition to a smaller carbon footprint, is substantial savings on monthly energy costs.
One myth about retrofitting a building for higher energy performance is that you’ll have to scrap all of your old systems and replace them with better ones. In fact, while you may benefit from replacing some of your systems, there is ample room to improve your building’s performance by optimizing the systems you already have. For this reason, the retrofit process should Roof with a white reflective material adds efficiency always start with an assessment of how your current systems are running. Three systems in particular—HVAC, lighting and building envelope—offer excellent opportunities to improve building performance without having to start over from scratch. Systems with large motors tend to be the biggest energy hogs, so we recommend starting your quest for better building performance in your HVAC plant. But, before you decide to replace your chiller altogether, find out if your existing system is functioning as well as it can.
Much as an engine tune-up helps a car run better by restoring mechanical integrity, a plant tune-up is essential to keeping your HVAC system running optimally. Have a plant tune-up twice a year. A few small adjustments can make a big difference in system efficiency, and the energy savings will certainly offset the cost of the procedure.
Once you have your plant running properly, check to see if your HVAC is pumping too much chilled or hot water through the building. Over time, manual or balancing valves get opened and forgotten. As a result, your system may have insufficient water flow to satisfy your current heating or cooling load. Address this issue by having your building balanced—not just during a retrofit, but regularly as your facility ages. Now, let’s talk about lighting: How many times did your dear dad remind you to turn lights off when you aren’t using them? Yet take a stroll down Peachtree after business hours and what do you see? Lights left on everywhere! There’s a significant monthly savings to be gained just by improving your light management.
For starters, make sure your facility has appropriate lighting controls and that they are set properly. Controls may include dimmers that allow end-users to select lower light settings or occupancy sensors that shut lights off when employees forget.
Whichever controls you choose, make sure your existing switches aren’t set to override them.
Finally, let’s take a look at the building envelope. You know how people are always saying they cut their home heating and cooling costs simply by sealing gaps in windows and doors? Well, the same is true for commercial buildings.
An infra red inspection is an inexpensive way to examine exterior building surfaces and identify the greatest areas of heat loss/gain as well areas where you may have water infiltration. A visual inspection by a trained professional will also do. Look for places where outside air and moisture are coming in and conditioned air is escaping. Replace caulking, seals or glass sections accordingly.
You may also consider replacing windows with Low Emissivity (Low-E) glass. The special coating on Low-E glass allows short wave light and solar energy to pass through but prevents the long wave energy produced by heating systems and lighting from escaping. Though it’s usually manufactured with new glazing systems, Low-E coating can also be field applied to existing windows. New refurbishing methods allow this to be done without disturbing interior finishes.
As for your roof, think of it as a hat: It protects your building from the elements, keeping you warmer in the winter and cooler in the summer. Because your roof membrane and insulation system are critical to both the livability and efficiency of your building, you may consider replacing the entire system—or just the top membrane—with a white reflective material.
In summary, retrofitting your building for better energy performance may call for some new systems, but there are also plenty of relatively inexpensive ways to get better performance out of what you already have. Always begin a retrofit project with a careful assessment of existing systems. You may be surprised by what you find and, more importantly, what you can save.
REED THOMAS & PAUL BENNETT