SUSTAINABLE DESIGN CENTER 
STRATEGIES & TECHNIQUES
Climate Considerations in Sustainable Design
Climate data is one of the most important elements of any sustainable design project. Analysis of that data must be much deeper than that historically performed in systems design.
In the old days, engineers often looked at the highest and the lowest annual temperatures and designed accordingly. Today, we must look at more than that. In every PAE design project, we look at 8,760 points of climate data. If that number isn't instantly recognizable to you, it's the number of hours in a year. And, we look at the temperature, humidity and wind in each of those 8,760 points.
Temperature Bins and Design Temperatures
Temperature Bins allow design teams to examine local temperature variations. We use this data along with cooling and heating design temperatures, to optimize a building’s envelope and determine its HVAC systems’ ideal type and size.
Precipitation Profiles
Approximately 225,000 gallons of rain falls on a 10,000 sf roof in Seattle each year.
Knowing the quantity of precipitation that falls on a site each month or year is essential for accurately designing a rainwater reclamation system. We use this precipitation data and information about the water’s intended use to determine the size of storage tanks. Such water is used for purposes ranging from daily toilet flushing to summer irrigation.
Incident Solar Radiation
Also referred to as “insolation,” Incident Solar Radiation is the amount of solar energy reaching the Earth’s surface at a given location. After a series of calculations, this measurement is an initial step in determining how much energy can be produced in a single location from a photovoltaic or solar thermal system. In many parts of the country, if a building produces more electricity than it requires, the excess is returned to the electrical power grid and counted as a credit toward the building’s energy bill.
Peak/Average Wind Speed
A wind rose gives detailed information about wind directions and frequency for a year or portion of a year. The radial bars show the percentage of time that wind blows from each direction for various ranges of speeds. This information is necessary for assessing the feasibility of wind power and some types of natural ventilation systems in a given location. Where possible, PAE installs anemometers at the site, as wind velocity and also wind consistency are location specific.
Generating energy from wind: Average wind speeds of 10 mph minimum are needed to generate energy from wind. Wind speed and energy generation have a cubic relationship: as wind speed doubles, the power generated increases by a factor of eight.
Tapping wind for natural ventilation: When exploring natural ventilation as a replacement for mechanical cooling, it’s important to reference a wind rose for the local cooling season, not a full year. It’s likely that the two are substantially different.
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