ReEngineering the Engineer: Sustainability: How Can We Help?
At about the time I was leaving my old firm in 2004, one of the large national architectural firms we worked with made a corporate announcement. Their firm would be focusing on the green movement (predominantly LEED at the time) and were committed to designing their buildings to be more sustainable. They planned to have everyone in their firms, presumably the architects, achieve LEED certification within the next year, and they were asking all their consultants to do the same. They wanted everyone on the team pulling in the same direction and be able to approach their clients with a cohesive, well-oiled, green machine.
I had worked with this firm before and had a good relationship with one of the senior project managers, so I purchased my LEED study guide and went to work preparing for the exam. The studying wasn’t particularly difficult: mostly common-sense things with some science to back it up. Honestly, I didn’t know much about sustainable design at the time, so it was exciting to learn something new and feel contributory to the green effort.
Sadly, however, I quickly discovered there wasn’t a lot of structural “meat on the bone.” There was adding fly ash to concrete mixes to reduce the carbon footprint from manufacturing cement; we were already doing that. There was specifying our building materials with high percentages of recycled content; a great idea, but structural steel already had very high percentages of recycled content anyway, so there wasn’t much there.
There were plenty of MEP things to do: solar shading, more-efficient heating and cooling systems, transferring light deeper into the workspace, solar hot-water heating, LED lighting, and so on. Similarly, there were architectural and finish options for choosing material that were friendlier to the environment, such as eliminating VOC content. Even the general contractor can help by capturing jobsite waste and being more efficient.
What About Engineers?
It seemed everyone else gets to have fun figuring out ways to make our buildings and construction better for the environment except us structural engineers. So how can we help? How can we contribute and feel like we’re part of the game? The answer: “When life gives you lemons, make lemonade.” Our solution was to try to understand what everyone else was trying to do so we could tailor our engineering to help facilitate those goals.
One of the easy, low-hanging-fruit ideas has been roof-mounted solar panels and solar hot-water heating. Our job was to develop some clever ways to support these items on the roof but also allow for flexibility in maintaining the roofing. The solar panels generally were pretty light and didn’t require much transformation in our usual designs. The solar hot-water-heating panels typically were heavier and larger, and required some more-creative thought.
Recently, I talked with one of our local MEP experts in green engineering about some of the things he’s seen recently (and not so recently) that are challenging designs for structural/civil engineers. Here’s a short list of some of the interesting ideas:
Wind Turbines on Buildings
The Bahrain World Trade Center (2008) claims to be the first building to incorporate this type of green thinking. The designers were targeting an 11 to 15 percent supplement to the building’s energy demand and, according to recent reports, are achieving those returns. There are several other buildings—some very recent—that have incorporated different styles of turbines. Yet there are some significant structural challenges with all these—vibration and noise being the obvious ones, but predominant wind direction and turbulence also play significant roles in the ultimate effectiveness. Although the concept sounds feasible, there are plenty of mixed results on their effectiveness.
Generating Power from Streets
How about generating power from an already existing infrastructure: the roads we drive on? There are several different concepts. One makes use of piezoelectric crystals or ceramics embedded into the roadbed to convert vehicle vibration into electrical energy. Another uses hydraulic devices that are a more-mechanical conversion. Even speed bumps are getting in on the action with hydraulic, pneumatic, mechanical, electromagnetic and piezoelectric devices. All these concepts generally store their energy into batteries for potential use on nearby devices such as street and traffic lights.
On the collegiate side, there’s a competition called “Solar Decathlon.” It’s mostly a residential-building competition in which schools from all over the world assemble at inspirational settings, build homes onsite and then have them tested over a week-long period. According to the decathlon website (www.solardecathlon.gov), the contests evaluate cost-effective design; innovation balanced with market potential; water and energy efficiency; energy production and time-of-use energy; and communications strategies. They also are governed by rules to ensure fairness and building codes to ensure life safety. Failure to follow rules can result in point penalties. Failure to comply with building code requirements can result in disqualification from the competition.