5 ways to achieve high-performance buildings using energy modeling
For the Mall of Saudi, early energy model and daylight simulation were conducted to determine energy conservation measures and to design skylight. Photo courtesy of AIA
In sustainable design and architecture, it can be hard to keep up with ever-changing approaches and methods. But it's also incredibly important to take advantage of sustainable methodologies like energy modeling.
Here are five tips on using energy modeling in your next project that can both tap into its benefits and be easily explained to your clients.
To reap the long-term environmental and fiscal benefits of energy modeling, it's important to use energy models early in the design process, especially during conceptualization. This involves assessing all design options in the envelope, lighting, and mechanical systems before moving forward. Energy modeling does not require the use of a 3D model; it can be completed with just the massing information and project parameters, including building type, operation schedule and typical occupancy.
ASHRAE Standard 209P, Energy Simulation Aided Design for Buildings Except Low-Rise Residential Buildings is a good resource for energy modeling early in the design process.
By beginning energy modeling early, CallisonRTKL has seen an average 10 percent increase in energy performance compared to projects that do not implement early energy modeling. And compared to non-modeled buildings, modeled buildings have a 20 percent better energy performance. The International Building Performance Simulation Association provides basic information about energy modeling.
Collaborate with other teams
Collaboration is one of the most effective ways to get fast, innovative results; it is even more critical in energy modeling. Buildings achieve higher performance when architects work directly with the energy modeler to determine building envelope assembly and design, rather than coordinate through the mechanical engineer.
Independent energy modeling consultants may be more familiar with the early collaboration process, and it is recommended that large architecture firms establish an internal energy modeling group to facilitate collaboration between groups.
The choice of energy modeling software is also important to facilitate collaboration. Department of Energy-based and EnergyPlus-based software can help to avoid any licensing issues, as both platforms are free. Savvy clients may also ask for the energy modeling file for reference during the measurement and verification process.
Track energy performance during the process
After early design energy modeling is complete, it’s important to continue to track energy performance all the way through construction.
The 20-20-10 rule can be implemented to improve the accuracy of energy model results. The diagram above illustrates this rule; if you complete an energy model that shows 20 percent savings above energy code in early design, your final building energy savings should be within 16-24 percent better than energy code. If all assumptions—building usage, occupancy, weather—are correct, the real energy usage will be no more than plus-or-minus 20 percent the final energy model.
Energy models can be included in project submittal requirements. The ASHRAE 209P standard can be used to determine the submittal requirements for each step. Working closely with all teams as the process continues will improve final project performance. This includes providing the HVAC engineer with your envelope information, including assemblies and detail drawings, before he or she begins to avoid oversizing.
Provide a smart financial assessment for your client
By using energy modeling and lifecycle cost analysis, you can teach clients about the return on investment and financial impact of investing in energy efficiency. It is also essential to collaborate with a cost consultant or contractor during the early stages of design to select the best investments for energy savings. During the evaluation process, the envelope design and the mechanical sizing impact should be assessed together to reduce overall mechanical sizing for the project, which will also reduce initial building costs.
The team can also check local utility incentive programs for high-performance buildings. Programs like Savings by Design may provide incentives for design teams as well. As an example, one of CallisonRTKL’s projects received a $40,000 incentive because its energy performance exceeds local standard code.
Check the envelope requirement before submitting to the city or LEED
The architect of record is always responsible for the envelope design in energy compliance reports. This also means that the architect is responsible for checking the energy report during envelope assemblies before signing the energy documents.
By implementing those five rules, project teams can achieve optimal performance in energy usage. As the AIA 2030 Commitment's 2014 Progress Report pointed out, energy modeling is critical to reaching the goals of the Commitment.
It takes time for a design team to capture the maximum value of energy modeling. Typically, after two or three projects, design teams are able to better utilize energy modeling information and speed up the process because more early decisions can be made based not on initial cost but long-term value.
Written by Eddy Santosa, an energy modeling lead in CallisonRTKL’s Seattle office.
Companies: The American Institute of Architects