EVALUATING the PORTLAND BUILDING with the RETROFIT SAVINGS ESTIMATOR
The Portland Building is an iconic example of postmodern architecture occupying an entire city block in downtown Portland, Ore. The building features various unique design elements, including the hammered-copper Portlandia sculpture above the main entrance. Unfortunately, the building also features more than its share of problems: extensive water intrusion, sloped floors, uneven lighting in work areas and ventilation issues are just a few. This all means the Portland Building is a good candidate for a deep retrofit. But just how deep and how big is the energy-savings potential? We at New Buildings Institute, Portland, ran the building through the Retrofit Savings Estimator to find out.
Preliminary Information
First we entered some basic information about the building. This is the kind of information that a building owner or operator will usually know, and some of it is information that can be obtained just by looking.
The information entered at this stage is used to figure out which measures are most important, so the tool can narrow down its focus. For example, if the potential energy impact of adding insulation to the roof is only 1 or 2 percent, the tool will probably ignore that measure in favor of strategies saving more energy. This first step means you never have to answer questions that aren’t directly relevant to the most impactful retrofit strategies.
Basic Inputs
Once the Retrofit Savings Estimator runs through its first round of calculations (there were 35 custom simulations, which took about a minute to run in total), we get to the second round of questions. At this point, the focus is narrowed down to six key measures. The estimating tool will consider between four and seven measures for each building in this step.
These questions help the tool determine the energy-savings impacts of specific improvements. For example, if one measure being considered is adding roof insulation, it’s helpful to know how long the current roof has been on the building so we have an idea of how much insulation is already there.
But what if you actually do know the Solar Heat Gain Coefficient for your windows? Or if you want to enter the specific U-value of your roof assembly, including insulation? That’s fine, too; there is a Detailed Inputs screen for those who can get more specific.
Results
Now that we have information about the building basics and about particular measures, the Retrofit Savings Estimator can really get to work. Hundreds of custom simulations are performed in seconds to investigate the effect of the selected energy-saving measures individually and in groups. This allows us to consider interactive effects between different measures; for example, installing higher-efficiency lighting can reduce the cooling load by decreasing the heat from light fixtures.
We see how much energy we can save by implementing the recommended measures. The energy impacts are shown as a percent savings compared to the building’s estimated current energy usage and to a building built to code in your area.
In the Portland Building, the total impacts could be as high as 59 percent of total energy use!
Customized Results
But what if we don’t want to pursue all of those measures? This final page of the tool allows selection of a customized package of measures to understand their impact.
In the Portland Building, the most impactful measures are HVAC distribution and lighting design. Let’s say, for now, we only want to focus on these and aren’t going to consider other measures. Those two key measures could potentially provide about 38 percent energy savings overall.
So what’s the outcome? First, we have confirmed our suspicions that the Portland Building is ripe for a deep retrofit. We also have some ideas about where to start and how much energy could be saved. And we were able to do this all for free and in about 15 minutes!