How to Design the Most Sustainable Urban Office Building, Part One
The process of getting San Francisco Public Utilities Commission’s (PUC) new headquarters at 525 Golden Gate to gain the reputation of “Greenest Urban Office Building” was a labor of love. From a comprehensive wind study to design ideas that included embedding solar panels directly into the window panes, the KMD|Stevens team forged new ground every step of the way. At the end of the day, the sustainable architectural elements included in the design will generate 7% of the building’s energy needs, enable the building to consume 32% less energy than similarly sized buildings and earn the rating of LEED Platinum.
So how was this possible and how can it be used for your next project? Let’s take a look:
Step 1. Define what you mean by “green”
The first step is to make sure everyone is on the same page with what they’re working toward. The term “green design” is still somewhat amorphous. What is sustainable to one can be completely wasteful for another. The key here is to work with the clients to identify what is green design for them.
For the PUC, this meant looking at the full life of the building and the employees who would be working there. Where are they coming from? How far away do they live? How are they going to get to work? The PUC wanted to build in a place where using public transportation wasn’t just encouraged, but made the most sense. These desires made it necessary to establish the headquarters in a dense urban environment.
Additionally, considering that the PUC is a utilities agency, it was important to look at the type of energy they made. A thorough investigative analysis found that PUC’s energy was cleanly produced through a variety of means including hydro and solar power. Designing the inclusion of a fuel cell on the buildings just to be totally off grid didn’t make sense in that it would add up a larger carbon footprint in the long run. To maintain the integrity of the sustainability pursuit without adding unnecessary measures, the team decided upon a blend of technologies – some traditional and others more maverick – to gain the status as the greenest urban office building.
Step 2. Look for energy conservation
Before diving into how to make new energy, always look first for opportunities to conserve. The more you conserve the less need you have for generating new energy. To start, ask some key questions and pick up all the low hanging fruit you can find. What are the natural benefits of the site? How can we leverage sunlight or water or rain? What is our relation to our neighbors? How can we utilize the shade of neighboring buildings, and where do we need to continue to provide our neighbors access to sunlight? You may find that the site is perfectly situated to offer multiple options for energy generation.
When you start going beyond these easy grabs, the design team can flex their creative muscles to identify a number of opportunities, however you need to understand whether or not there is some flexibility with occupant use. For instance, is the client willing to let employees wear shorts on hotter days to allow a change to the temperature set-points thereby reducing demand? Would the employer be open to promoting a program to power down electronics when not in use? Encouraging occupant behaviors can support reduction in plug load use and ultimately a reduction in the amount of energy used on a given day.
Among other things, the PUC’s easy grab was leveraging the natural climate of San Francisco to heat and cool the building throughout the day without overusing the chillers. Using thermal mass of concrete allowed the building to store heat generated throughout the day and flush it at night. The nighttime flush chilled the floor slabs, cooling the building’s temperature for the better part of the following day and minimizing the use of chillers to cool the interior spaces.
Step 3. Be creative with your energy
Consistent with Steps 1 and 2, Step 3 begins by looking at what the site affords you and where your desires lay. Is your site in a particularly sunny or windy location? Like the others, this one is all about working with what Mother Nature gave you.
In San Francisco, we’re blessed with both sun and wind. Photovoltaic panels have been around for a little while now and their science is proven. But the big win of the day came with harnessing the wind that blew through the city day and night. To see if this was a viable option, the team looked at historical data on wind speed and direction collected on neighboring buildings. Additionally the team built a wind tunnel model to study wind speed in relation to the building. The findings indicated a tremendous opportunity for energy generation and we set to work designing a building that could maximize this gift.
What results is a wind tower on the north side that resembles a glass airplane wing. The curve and angle of this tower serves to accelerate the speed and force of the wind moving over the building’s surface, maximizing the benefits of the captured energy. Combined with the solar panels, the building can generate up to 277,000kWh/year.
Coming up in Part 2…
The PUC wanted their new home, 525 Golden Gate, to be a teaching tool for sustainability. The design demonstrates how green efforts have a positive architectural effect. In Part 2 of this series we’ll take a more in-depth look at water, how it is used in the building and the unique way the design team found for onsite water treatment.
What to do next
Are you wondering what sustainable options may be available for your next project? Download our easy guide to get started figuring out which options may be right for you.