This is a report on the zero emissions building virtual design charrette that took place in HOK’s Advanced Collaboration Rooms in San Francisco, Toronto and St. Louis on 31 July 2009. Lots of video clips at the end!

This meeting began with a restating of the goal of designing a zero emissions building design that will reduce the energy requirements for a traditional St. Louis office building of 150,000-200,000 square feet by 70-80 percent. They will use on-site renewable energy sources to get the rest of the way to zero emissions.

Because energy conservation typically costs less than energy generation, the team is using off-the-shelf technologies to design a building that consumes 17-18 KTBUs per square foot per year. This compares to a base case building that uses 65 KTBUs. The team acknowledged the importance of cutting as much energy consumption as possible from big categories like lighting, heating and the building envelope.

Net Zero Energy vs. Net Zero Carbon Emissions

HOK Director of Integrated Design Gerry Faubert reminded the team gathered around the virtual design table that the solutions are not the same for net zero energy and net zero emissions buildings – and that the most energy-efficient buildings will not necessarily achieve carbon neutrality.

“This study has helped us learn the difference,” said HOK St. Louis Sustainable Design Practice Leader Tim Gaidis. “It’s interesting to think about what that will mean to the building cost as it gets marketed. As carbon cap and trade comes to pass, maybe there will be a monetary value placed on the net zero carbon building that doesn’t exist now.”

The team needs to recognize that zero energy buildings are not the future of U.S policy, said The Weidt Group’s Prasad Vaidya. “Zero energy is a good exercise for understanding how to make really good decisions for energy efficiency. However, zero carbon is more desirable for a future in which climate change and carbon trading are expected to become much more important. Zero carbon will actually be a fungible amenity.”

“We are after zero carbon,” agreed HOK Chairman Bill Valentine. “And the path to carbon neutrality is all about energy efficiency.”

The Weidt Group’s David Eijadi reminded the group not to seek out a zero emissions “silver bullet,” and urged them to keep pushing to overcome long-held approaches to designing buildings. “Change is hard but we want to live in the future.”

Eijadi described a “Cost Tunnel Effect,” which theorizes that the cost of adding energy efficiency into a building increases as the design team tries to squeeze in more technologies. “But if you can change the architecture to reduce the need for technological systems while achieving efficiencies of 70 percent,” said Eijadi, “the cost theoretically begins to go down. We’ll see if this holds true for a building of this size in the St. Louis climate.”

Entropy and Energy Purity

As part of his detailed energy modeling review of the team’s four building massing schemes, The Weidt Group Energy Analyst Chris Baker explained the idea of entropy and energy purity.

“Energy can be more or less concentrated,” he said. “The most concentrated types of energy are light and electricity. We will be most efficient if we can meet energy needs with similar energy states. For example, this means using daylighting for lighting and lower grade heat such as solar thermal for energy. Daylighting is going to be especially important because we are paying a carbon penalty to get that more pure energy for electricity.”

Massing Model and Site Discussions

The team’s ability to daylight the building as much as possible will have a huge impact on its ability to reach zero emissions.

HOK Chicago Architectural Technician Jeff Sanner presented an Ecotect daylighting massing model analysis showing that each of the four ‘bar building’ schemes the team was considering would provide approximately (within 10%) the same amount of daylighting.

After much discussion of the energy and daylighting analyses and drawing on the virtual flipcharts, the team agreed that the design would be for two slightly offset, four-story vertical bars that are 250-300 feet long and 65 feet wide. The two bars would sit at least 60 feet apart, with one or two 30-by-80-foot connectors linking the two bars.

Though some were concerned about the length of the bars, it was suggested that the length that would be less of a concern if they opted to include connecting links at both ends. “We need to allow ourselves the length we need to get the maximum daylight,” said Lazarus.

The team agreed to explore what would be in those connectors, be it some combination of tenant circulation space, core functions or offices. Key to the design will be to ensure that the building remains flexible for multi-tenant occupancy in a marketable speculative office – and to preserve the daylighting into the building.

Tyler Meyr of the HOK Planning Group in St. Louis presented a series of massing models that fit within the boundaries of the 490-by-420-foot site. Meyr’s schemes added green space, broke down the linear scale of the buildings and explored parking options.

The team determined that to provide the required 400 parking spaces with using underground parking – both for budget and energy-consuming ventilation requirements – would require a combination of structured and surface parking. They resolved to use the roof of a proposed 120-foot-wide garage to harvest energy via photovoltaic panels.

“We could build half the garage upfront and the second half later,” suggested Michael Clark of developer Green Street Properties.

Energy Saving Strategies

Baker reviewed a long list of potential energy conservation strategies that his team was modeling. The strategies included dozens of options for the envelope, window glazing, window design, daylighting control, lighting control and design, lighting technology, cooling efficiency, heating efficiency, HVAC and plug load.

Senior Cost Estimator Frank Kutilek of HOK Construction Services will provide cost analyses for each.

“By showing the energy results and cost implications at our next team meeting,” said Baker, “we will see all the different ways to get to 10-20 KTBUs per square foot and get a better idea what we can accomplish through design.”

What Did We Learn Today?

Lazarus concluded the day by going around the virtual room and asking for each team member’s “a-ha” moments.

“This collaboration and combination of design expertise is going to get us to a really different result,” said Faubert. “We are focusing on energy and carbon, but in my mind this is a completely refreshing and the absolute right approach on how to design a building. If you want to have a different result, you have to change the formula. This could change the way we work.”

“This integrated process is fantastic,” agreed Alan Bright, a senior designer in HOK’s San Francisco office. “We should do this on all our projects, though we should have involved a structural engineer.”

“I know how easy it is to rely on rules of thumb and past experience,” said Eijadi, who spent the early part of his career designing projects as an architect. “When we started this morning, I thought ‘I don’t know if we will be able to convince some experienced designers here that they can look at this differently with different information.’ Whenever we start a process like this, it is always a gamble. We don’t’ always change everyone’s mind. I was gratified with the outcome today.”

“Collaborating so closely with architects and engineers to come up with a solution is a good reality check,” added Vaidya. “We always think of ideas in analysis, and this is a good way to bring them to design.”

“I appreciate that we are getting involved in the process earlier for the costing,” said Kutilek. “Our whole goal in costing is to allow the design team to find out the costs so you don’t have to go back and revise your drawings more than once.”

“This has been tremendous fun,” said Baker. “We often work with architects, but at arm’s length. To be in here while you all are designing has been fantastic and eye-opening.”

Gaidis’ a-ha moment came with Baker’s discussion of entropy. “I had never made the real connection about levels of energy,” he said. “That allows me to think about how to use energy and how to apply the different renewable energy sources. We talked about the path to carbon neutrality being through energy efficiency. I would extrapolate that to say here that the path to all our success – to carbon neutrality, energy neutrality or operations cost minimization – goes through energy optimization.”

Meyr likes the accelerated process. “Because of the instant feedback with a diverse group, we can move from assumptions to decisions faster than usual,” he said. “It’s nice to make such quick decisions so we can move forward.”

“I am pleased the solution has been focused on being marketable,” said Clark. “I am anxious to see the end result in terms of how close we get to the numbers we need for zero carbon. It won’t be that we get there and then can’t sell it. And that is important.”

Eijadi reminded the team that they are challenging the frontiers of cost and design. “The outcome may be we can almost get there and still sell it,” he said. “That would be just as good.”

Lazarus expressed her relief that the design team was not feeling constrained by the goal for a 70 to 80 percent reduction in energy use. “It is actually liberating,” she said. “I was worried that we would have a design by model, with an answer that is the result of all these analyses. But it is allowing us to see where we need to be most creative. We hope it will allow us to make decisions that will really drive to this zero emissions performance we are seeking.”

She also noted that it is “interesting to understand the differences between our natural tendencies and what The Weidt Group and the Biomimicry Guild say to us: ‘Think before you draw. Let us help you understand the implications before you make those decisions.’ I appreciate everyone being open to that.”

“We always talk about the idea that you can make a baby with nine months and one person but you can’t use nine people to make a baby in one month,” said Gaidis. “I actually feel like we are making a baby in less than nine months.”

 Previous ZEB posts:

1. Onward to Zero Emissions
2. Onward to Zero Emissions – Part 2
3. Weidt Light
4. Zero Emissions Building Charrette #2 — The Paradigm Shift
5. Passing Virtual Notes
6. Zero Emissions Building Team Using Biomimicry as a Design Filter