Next-gen building energy codes pilot in New York
New 100% performance based energy codes developed by Pacific Northwest National Laboratory (PNNL) are being piloted in New York.
This new approach to energy codes using tools developed by PNNL is aimed to simplify compliance and pave the way for more energy efficient city buildings.
A performance-based code determines compliance based on the projected energy performance of a whole building or its systems. These projections in turn rely on energy modelling and simulation tools to account for interactions between systems and components.
Conversely, the prescriptive approach, which has been the standard in building energy codes to date, considers a building compliant only if a set of requirements for individual components is completed, like a checklist.
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“This pilot is unique because for the very first time, we are testing the removal of the prescriptive approach that has always been used in energy codes,” said PNNL mechanical engineer and lead tool developer, Supriya Goel.
“With the prescriptive approach, if one thing is not done exactly, the whole building is considered non-code compliant.”
The pilot between PNNL and the New York City Department of Buildings launched last year and was recently extended for a second phase.
In the US buildings use 75% of the nation’s electricity and 40% of its total energy, which accounts for 35% of the carbon emissions. Buildings thus have the potential to contribute substantial energy savings.
In New York City, buildings produce nearly 70% of the city’s greenhouse gases. Energy codes that result in more efficient buildings will play a key role in helping the city meet its goal to be carbon neutral by 2050.
The 100% performance-based energy code developed by PNNL offers two ways to show compliance. One way is to assess whole building performance, which mirrors the current national energy code standard for commercial buildings but reflects NYC’s own policy goals and energy code requirements.
A second option evaluates energy performance at the building systems level, such as HVAC, lighting and envelope.
With the system-based performance approach an improved system with a shorter lifespan, such as an HVAC system, could make up for a less efficient system with longer term impact, such as the building envelope. By encouraging such trade-offs within a system, more flexibility is available to evaluate the building’s energy efficiency.
During the second phase of the pilot the aim is to draw on learnings from the first phase to refine the tools and expand to include more projects.
