Competition Drives SERA to Net Positive
Last month, a team at SERA finished the design of an apartment building that produces more energy than it requires. By using existing technology in an innovative way, they’ve created a model for future development they call Flourish.
With all the hallmarks of a big firm project, Flourish is actually a submission for Architecture at Zero, an international design competition to innovate net zero energy buildings that meet California’s approaching commercial and housing construction guidelines. SERA staffers accepted this year’s challenge to design affordable housing on an existing lot in Oakland, California.
With experience creating some of the most recognizable LEED-certified buildings in the region, the team had ambitious goals to go beyond energy equilibrium.
“We all felt like achieving net zero energy was the easy part,” said team member Nathan Burton. “But how do we integrate sustainability with livability and community in affordable housing, and still make it elegant?”
Before any concepts like building shape or footprint were decided, the team considered how to make use of the region’s ample sun exposure.
Using modeling software, the team determined where sunlight hit the lot and crafted a structure around it. The result is a public space-oriented design that snakes along a narrow site, dipping and rising to accommodate sunlight along its façade. Even in areas where the building curls in on itself to create semi-private courtyards, there’s sunlight.
Understanding the value of integrated design, the team worked with energy consultants at Glumac to develop a building that seamlessly works with its environment. A partner of SERA’s on award-winning sustainable design projects like the Edith Green – Wendell Wyatt federal building, Glumac uses its own 3D energy modeling to test and refine designs using simulated conditions.
Energy analyst Brian Goldsmith helped the team strike a balance between energy production and use.
“It’s rare to get the chance to throw ideas around without any of the barriers of a typical project,” Goldsmith said. “We were excited about going for net zero on this project.”
Using weather data for the Oakland area, the team decided on powering Flourish entirely with solar energy. Traditional rooftop photovoltaics cover the majority of its roof, while bifacial photovoltaics act as translucent canopies over a wide swath of shareable rooftop space. These elements provide all of the electrical needs of tenants and building operations.
The sun also greatly reduces the demand for mechanical heating in the building. Solar gain from the south, east and west-facing windows, coupled with a highly insulated building envelope, provides the bulk of heat needed in most of the units. The system of solar thermal panels preheats water for occupants while also providing additional radiant heat in the coldest winter months.
None of these features would be as useful, the team notes, without structuring the building around the sun.
In order to make Flourish net zero, generating energy was just the start. The team would also need to make it easy for occupants to adapt to energy-saving behaviors without depriving anyone of the typical comforts of home.
Since Flourish is oriented to maximize sun exposure, the units rely on a few built-in features for controlling the temperature. An array of manually-operated exterior shades controls the level of sunlight penetration in the building. This feature maximizes solar heat gain in the winter and deflects the hot rays in summer months.
Meanwhile, the single-loaded design of the apartments promotes air flow through each unit. Occupants can manage the circulation by opening interior doors and transom windows, and use ceiling fans on windless days.
Project team members viewed both of these systems as energy-saving measures as well as engagement tools for residents. Giving occupants a way to control their environment is an aspect often missing in affordable living environments.
Too bright or too warm? The occupant decides which features to use.
According to Goldsmith, a traditional building the size of Flourish has an energy use intensity (or EUI) of between 35 and 40. EUI is a calculation of a building’s annual energy usage per square foot; the lower the number, the better the building’s performance. The project team’s initial design started at 25 EUI, and by the end reached between 10 and 15 EUI.
The sunny semi-private courtyards at Flourish link to a larger green space of trails, native plantings and gathering areas adjacent to the building. The team envisions these spaces as grounds for neighbors to connect.
“We wanted to address the negative connotations affordable living,” said team member Matt Piccone, “Flourish creates a community feel through nice, safe places that give residents a sense of ownership.”
Rooftop gardens and double-height community rooms about every eighth unit allow residents to entertain, prepare shared meals and relax. A ground-level daycare that doubles as an events space in evenings adds liveliness and play to public spaces.
By bringing occupants out of their units and into central areas, they’ll also share resources and use less energy through an economy of scale – an opportunity not missed in this design.
“We’re giving residents a reason to turn off the TV and go outside. We’re saying, ‘have a barbeque, and get to know your neighbors!’” Piccone said.
Flourish grew from sketches on a pinup board to a buildable design during lunch break meetings and after-hours modeling. In that time, a team of six shared ideas, hosted charrettes and continually refined the project. The enthusiastic team includes Nathan Burton, Matthew Piccone, Mark Perepelitza, Artur Grochowski, Katie Felver and Jeffrey Maas.
In the end, they showed that not only is it possible to use existing technology to achieve net-zero energy performance – the final project can actually be net positive. And even with limited time, a great team can accomplish a lot.
“If we had only one week to explore a design, what could we do?” asked Burton. “It would be this.”
Winners of Architecture at Zero will be announced December 5.
This is pretty cool, though I kept looking for the part of the story re: how to make this affordable housing affordably. Was there any financial analysis done on the cost for building Flourish?
Joel, great question! The competition entry was focused on reaching the energy and place making goals described, though you’re completely right that cost-effective construction would be critical to making such a project possible in the realm of affordable housing development. While this was not a primary focus of the entry and no cost analysis was done within the limited time available, that’s definitely a key piece of this design that could be developed further.
The forms and design elements are based on structure and envelope systems that have been proven to be available and relatively cost effective in the market. It utilizes common wood framing over a concrete podium, cellulose and mineral fiber insulations, cost effective air and water barrier techniques, and window systems that are proven to balance cost with performance. In addition, the mechanical systems chosen perform multiple functions and are focused on being simple and minimal. We believe these strategies would lead to a relatively affordable first cost design (though certainly above standard construction), though the real cost benefits would be realized over the life of the building through durable systems requiring minimal maintenance and the potential to eliminate most utility costs.
To make this kind of approach feasible, new and creative financing and regulatory strategies will be necessary to support deeply sustainable projects such as this, especially if society is to move toward a restorative model of development. There’s some really great info available along these lines in the International Living Future Institute’s recent Living Building Challenge Framework for Affordable Housing.
I think what the competition entry achieved was to show what’s possible; way beyond net zero performance and holistic community design that goes well beyond the norm. An overlay of realistic constraints is definitely within reach, but would be best accomplished in collaboration with experienced affordable housing developers and contractors.
Thanks for the feedback, and please keep the thoughts and questions coming!