This week marked the arrival of the September ASHRAE Journal in mailboxes across the region and profiled inside was the world’s largest net zero energy building, the Department of Energy’s Research Support facility located in Golden, CO. In contrast to the successful design highlighted in this article, the reality is that many design teams in our industry are still embracing a process that can result in a last-minute scramble to analyze additional energy conservation measures to include near the end of a project’s construction design phase. So, the question becomes, how do more projects move forward from a (not uncommon) predicament of late game heroics to an integrative team design process where netzero buildings are more commonly achieved?
With the ongoing advancement of energy savings stipulated by the LEED rating system, ASHRAE Standard 90.1, and the 2030 Challenge, early stage energy modeling is rapidly becoming an element of the traditional design process, instead of a novelty that only the most aggressive projects undertake. Primarily, this enables the energy savings burden to be partially lifted from the engineering systems’ selection and performance, and redistributed more evenly to all of the project team’s disciplines.
Last year, the AIA published “An Architect’s Guide to Integrating Energy Modeling in the Design Process” which defines the different types of energy modeling and the design stage in which they are to be most effectively used. Of particular note in this publication is Design Performance Modeling (DPM), which is performed during the early stages of design. The objective of DPM is to take the maximum advantage a project can from architectural strategies, including thermal massing, site orientation, envelope design, glazing percentage, and opportunities for passive cooling and heating, before the engineering strategies even start to be evaluated. This enables a project to passively gain energy savings from a building’s environmental climate.
Another energy end use in a building that can be addressed in early stage energy modeling is the anticipated process loads. Routinely, process load reductions are not something that design teams aggressively pursue with a Client. Due to LEED’s requirement to carry the same process load energy in the design and baseline energy models, any process load reduction might not help you obtain additional LEED points (although you could attempt to submit an exceptional calculation), but it will reduce your EUI, potentially enable the mechanical equipment to be downsized, and help assist in the achievement of netzero.
The advantages associated with early stage energy modeling are also starting to be acknowledged by some of the more progressive Owners. Cornell University, a signee of the President’s Climate Commitment, is one institution of higher learning that has pledged to have its main campus be net zero by 2050. In order to attain carbon neutrality, the University has taken steps to use carbon offsets; however, the offsets are a backup plan to its primary agenda of reducing the amount of carbon it produces. To further this goal, the University has developed a design standard for their building projects that states their EUI energy targets and details their energy modeling requirements for each stage of the design process from conceptual thru construction documents.
Too often, project buildings’ design, with respect to achieving energy savings, is seemingly being determined on “form follows precedent” instead of “form follows function”, but early stage energy modeling is one of the most effective tools a design team can undertake to successfully achieve energy goals.
Carrie Platusich is an Energy Engineer at Vanderweil Engineers in Boston, Massachusetts.