MAXIMIZING BUILDING PERFORMANCE: THE CASE FOR EARLY-STAGE ENERGY MODELING
Designing a commercial building is a complex undertaking where small choices can have a big impact on performance, efficiency and sustainability.
Traditional building design often follows a linear process, which misses opportunities to capitalize on
synergies and efficiencies across a project. That’s why the industry is increasingly shifting toward Integrative Design (ID), bolstering collaboration among stakeholders — from building owners to architects, engineers and contractors —
on the desired outcomes from the start.
Energy modeling (EM) plays a crucial role, serving as a tool to evaluate design decisions that enhance and amplify the benefits of ID. By employing it in the pre-design phase, all stakeholders can better
understand how different choices will impact the overall performance, ensuring the delivery of a more efficient and sustainable building.
WHY CONVENTIONAL DESIGN APPROACHES FALL SHORT
Numerous assumptions guide the linear approach, from the pre-schematic phase to the final construction documents for contractors. This often involves designing various building elements, like HVAC, insulation and windows, in isolation.
MAKING EARLY, INFORMED DESIGN DECISIONS
Research shows that the cost of design changes rises as a project progresses; therefore, adjustments become harder to make. That’s why it’s crucial to get decisions
right from the outset — or to assimilate learnings and change tack as quickly as possible.
EM and ID help to identify design challenges early on, so it is easier to make critical decisions up top. While this may mean making some assumptions
and refining them as the project unfolds, this approach avoids on-the-fly changes, extra costs and delays.
Looking to accommodate a heat pump to meet electrification goals at an advanced project stage is a good example of this, as changes
in system types can affect the building’s space allocation availability, architecture and electrical system capacity.
Figure 3: Why making changes early is more cost-effective in the long run
Source: IDD: Integrative Design and Delivery (cec.org)
THE VITAL ROLE OF EARLY ENERGY MODELING
Making key decisions about the building at the initial stages also means bringing EM in much earlier. Traditionally, this has been done toward the end of the project to ensure regulatory compliance, and avail of rebates and other energy-efficiency incentives.
However, this approach misses the opportunity to harness the insights EM can offer in the early stages when key decisions are made, potentially limiting the design team’s flexibility. Gleaning insights earlier allows all stakeholders
to capitalize on the synergistic effects between the building envelope (exterior walls, foundations, roof, windows and doors), as well as lighting and HVAC.
What's more, there’s potential to identify and agree on the building’s
energy goals from the start — and to be ambitious but also realistic about the choices and compromises made.
As sustainability codes, standards and regulations evolve throughout the US, energy modeling emerges as a vital tool for harmonizing environmental priorities with core design objectives — enabling balanced, effective solutions that drive
greener, more resilient outcomes for buildings, businesses and the planet.
USING EM TO MAKE BETTER DECISIONS
A 54,000 ft² office building prototype, compliant with ASHRAE 90.1 standards, was modeled in Denver, Colorado, using Daikin Applied EA Pro software, powered by the US DOE’s EnergyPlus simulation engine. Rebel® heat pump rooftop units
were assigned to serve the building. Two HVAC alternatives were analyzed for the heat pumps: (1) electric back-up and (2) gas back-up.
The Environmental Protection Agency’s eGRID emission factors, representing the greater Denver regional grid, were used to calculate emissions, along with average electricity and gas utility rates for the region.
The results indicate that while total energy usage is lower with the electric back-up scenario—due to the higher efficiency of electric resistance heating compared to gas combustion—the annual utility costs and equivalent carbon emissions
are lower with the gas back-up scenario. This is primarily because of higher electric utility rates and the electric emissions profile of the regional electric grid.
This example represents a specific scenario for demonstration purposes but highlights the importance of holistic, project-specific considerations when evaluating design alternatives to meet customer goals.
Figure 4: Weighing up air-cooled and water-cooled chillers
FINDING A PRE-SCHEMATIC EM TOOL
EM tools vary greatly, ranging from highly complex systems that allow for detailed modeling of every building component to much simpler solutions.
Many advanced tools require significant time investment, and model creation can take up to 80
hours. This has led to a perception that EM is too time-consuming and has prompted some designers and builders to avoid it altogether.
Recognizing a need for a more accessible solution, Daikin Applied developed EnergyAnalyzer Pro (EAPro),
a pre-schematic energy model tool, that is designed to support Daikin sales representatives in helping customers make informed decisions. It simplifies the modeling process by offering preconfigured building designs that can be customized with initial
project information.
EA Pro is built on the US Department of Energy’s EnergyPlus simulation engine, which is widely accepted by utility companies and rating authorities,
making it a credible and ideal tool for early project insights. It can also be used to assess the potential for securing energy efficiency rebates and tax incentives.
EM: A FOUNDATIONAL DESIGN ELEMENT
We’ve shown that EM is a powerful tool that can enhance the benefits of integrative design, helping teams make more informed decisions about efficiency, costs and meeting project timelines.
Rather than being an afterthought, early-stage
modeling should be a fundamental stage in the design process, allowing stakeholders to identify synergies and avoid costly revisions down the line. By choosing user-friendly tools that evolve with the project, design teams can streamline decision-making
and create more sustainable, high-performance buildings from the ground up.