HOK’s Sustainable Analysis Tool: Energy-Saving Design Solutions at Push of a Button
HOK’s Sustainable Analysis Tool provided early architectural strategies to optimize daylight and reduce energy and water use for the headquarters of Consumers Credit Union.
Climate and site data that once took days to gather and interpret now takes just minutes with HOK’s Sustainable Analysis Tool.
As sustainability and resiliency become more important, architects need new tools to ensure their buildings meet energy and operating goals from the beginning of the design process. That’s what HOK had in mind in developing the Sustainable Analysis Tool (SAT), a proprietary tool that quickly provides project-specific climate and site analysis and design strategies that maximize a building’s efficiency during construction and through its entire life cycle.
Prior to developing the SAT, teams could expect to spend at least a day (sometimes two) gathering detailed climate, project and site information required to inform a design. Once that data—such as historic weather averages, local energy codes and project benchmarking specifications—was collected, it could take another day or two to analyze the impact on design.
“This was a huge amount of time, particularly during the early stages of design when the team is often creating a concept in response to an RFP and without a project budget,” says Farid Pour, the key developer and programmer of SAT and a senior sustainable design manager with HOK’s Chicago office. “More importantly, big opportunities for cost effective and climate responsive solutions are often missed when the analysis is provided at the later stages of a design.”
Unlike other analysis sustainability tools, the SAT not only provides teams with climate and site information, it also offers schematic architectural design strategies that can help shape the early stages of design.
SAT’s input page (above) takes just a few minutes to complete with information readily found in project marketing material and dropdown fields.
How It Works
Using the SAT is easy. Design teams only need to know a few key specifications about a project, such as its location, estimated size, program (or project type), target energy goals and estimated completion year. Inputting this information generally takes five to 10 minutes. The SAT then retrieves climate, benchmarking and electricity grid information related to the site’s unique location from databases managed by the U.S. Department of Energy, Carbon Monitoring for Action and other tracking agencies. Once that information is gathered, the SAT applies the data to algorithms within the tool to generate project-specific design suggestions. Within seconds of running the program, the SAT generates a nine-page, project-specific report with standardized energy, weather and design graphics based, in part, on HOK’s Six Step Process to Sustainability.
“The graphics are important because with a lot of similar tools, the information display can be difficult to interpret,” notes Pour. “With the SAT, we created a universal language in our graphics that our designers can understand regardless of their sustainability expertise or location—be they in Chicago, Hong Kong, Dubai, wherever.”
The above graphics show climate data for a project in the Midwest. HOK graphic designer Daniel Meeker designed the SAT’s graphic interface to “provide a choreographed engagement to support data-driven results.”
The first half of the report examines a project’s energy use baseline and target benchmarks, as well as site and climate conditions. The report specifically addresses a dozen weather factors that may provide insights for passive energy use and savings, such as solar heating and natural ventilation (based on average wind speed, temperatures, humidity and radiation).
“With the SAT, we created a universal language in our graphics that designers can understand regardless of their sustainability expertise or location—be they in Chicago, Hong Kong, Dubai, wherever.”
The latter half of the report continues with a graphic interpretation of the project. But here the SAT begins offering design suggestions for reducing loads. These recommendations (see examples below) cover everything from massing and orientation to programming, planning, shading, building openings and material-related strategies.
The SAT’s load reduction strategies for the above project in the northern U.S. include compact massing, buffer zones within the building and south-facing windows for high-occupancy spaces.
“The first thing I look at in the SAT report are the number of heating and cooling degree days,” says Anica Landreneau, HOK’s director of sustainable design. “If they’re balanced over the course of the year, the project could be a good candidate for a geothermal system (ground source heat exchange). If the humidity at the site is high, that suggests there could be a great source of clean water from condensate. If precipitation is consistent throughout the year, we can size rainwater storage more cost effectively and look at how we can reclaim rainwater for non-potable uses.”
For a building in a colder region, for example, the SAT might suggest a compact massing to minimize conductive heat losses, buffer zones to protect against wind and a dark-colored facade to maximize solar heat absorption. For a building in a warmer climate, it may recommend slender massing to take advantage of natural ventilation, internal and external shading to reduce solar heat gain, and minimizing the building’s southern exposure (for projects in the northern hemisphere).
“What sets the SAT apart is its design interpretation,” says Landreneau. “It is not telling architects how to design the building, but it is giving them ideas before they put pen to paper. Other software doesn’t offer that type of guidance, especially this early in the design process.”
SAT in Practice
Since its initial release in 2012, the SAT has informed the design of HOK projects from Asia to North America.
For Consumers Credit Union’s headquarters in Kalamazoo, Michigan, the SAT recommended features such as a south-facing atrium that draws in daylight throughout the year (and solar heat during winter), shading strategies and appropriate glazing.
The protruding roof and west facade of Consumer Credit Union’s headquarters provide shading and mitigate glare (left). A multi-story atrium protected with glazing and shades offers daylight year-round and solar heating in the winter (right).
“The SAT tool was very useful in quickly helping to develop an initial understanding of the site’s environmental conditions and recommending strategies to address the pros and cons of its context,” says Domenic Salpietra, lead designer on the project and a regional planning leader with HOK’s Chicago office. “This allowed us to inform the building siting, materials and facade strategies to address the positive aspects of solar gain as well as the negative effects of winter prevailing winds early and quickly in the design process.”
The SAT helped designers assess massing and reduce energy demands for Will Rogers World Airport’s passenger terminal in Oklahoma City.
The SAT also informed the design of a new departures hall at Will Rogers World Airport in Oklahoma City that features lots of glass, including a two-story window facing the airfield. Visibility assists with orientation in a busy environment and celebrates the event of being at the airport. The SAT helped the design team determine how to maintain desired views while preventing excessive solar gain through the use of a large roof overhangs. The team incorporated a translucent skylight over a central circulation node to provide diffused daylight deep into the plan and specified fritted glass for the concourse clerestory with the aim to control glare within the tall, south-facing space.
“It is not telling architects how to design the building, but it is giving them ideas before they put pen to paper. Other software doesn’t offer that type of guidance, especially this early in the design process.”
“I would describe the tool as very intuitive and an objective gut check of massing decisions we often take for granted as architects.” says Casey Renner, a project designer with HOK’s Chicago office. “We’ve used it quickly, and early, in the design process on everything from airport terminals to courthouses, and it gives us almost immediate feedback as to how we can anticipate future design challenges or perhaps nudge our site orientation from a very schematic phase.”
HOK’s design teams have discovered another use that the SAT’s developers never intended: as a tool for impressing clients. “When we’re pursuing a project, I’ll run its site details through the SAT and bring that information to the client meeting,” says Landreneau. “Clients are always appreciative of the analysis and results. We’re showing them detailed challenges and opportunities for their project and site and climate information that they often don’t know themselves.”