Ask a Modeler: When is the Earliest in the Design Process That Useful Performance Simulation is Possible?

When is the earliest in the design process that useful performance simulation is possible?
– Early Bird Gets the Worm 

Dear Early Bird,

Where did the time go? Design evolves at such a fast pace that decisions must often be made based on partial knowledge. Because the design process is dynamic, every stage of the process presents its own unique opportunities for “early moments.” In order for a simulation to provide value and therefore influence a design, it must present information to its audience that empowers them to make informed decisions on relevant matters at that stage of design development.

Conceptual Design

Building form sets the load. With the earliest design decisions addressing building function, form, orientation, volume, and fenestration – massing and daylighting simulations can provide the earliest useful feedback to inform the optimal design of a high-performance building. Early massing models provide valuable insight into the trade-offs between desired aesthetics, site conditions, and energy goals. Daylighting simulation takes the building orientation and amount of glazing into consideration and can begin to shape the design of regularly occupied spaces. By minimizing glare and maximizing the daylight areas in the building, the output provided by simulation proves useful in addressing both occupant comfort and energy. While massing and daylighting address setting the load, an HVAC life-cycle cost analysis can be a great way to begin discussing load mitigation. Exploring multiple HVAC systems can give a high-level view of how a building will respond to a number of different factors including central/distributed systems, local weather, site feasibility, and energy/capital costs.

Schematic Design

Once the compass is pointing in the right direction, there is now an opportunity to refine conceptual models to gain a better understanding of the design concept. The results of the massing model can now be leveraged to further optimize the interior space layout. With the programming coming into focus, the daylighting model can be used to gain an understanding of the most efficient glazing configurations in order to maximize solar gain while minimizing the need for electric lights. Finally, as the selection of HVAC systems is narrowed down, early schematic design modeling can help plan for mechanical room sizing, plenum space, and mechanical closet distribution. It’s important to remember that each of these “early moment” models can continue to provide a new perspective and the most opportunity to influence relevant design decisions for the lowest cost.

Design Development

Finally, the design shifts to exploring building characteristics that will mitigate the loads. Early design development simulation can be utilized to model building envelope, lighting, and HVAC efficiencies that will give deeper insight into the tradeoff between measure-level efficiency, energy savings, and capital cost. While these measure-level model revisions provide the most detailed projection of the final building to date, they also serve an important role in justifying earlier decisions and ensuring those decisions carry forward from design and into construction.

Hopefully this provides a little insight into the early moments that happen throughout the design process so that you’re able to find a few “worms” of your own along the way.

Eric Flower
Software Account Executive, Willdan

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