Energy modeling use cases

An important step at the beginning of any project is to determine what value energy modeling can bring to the design. There are many common use cases, and many others that are less common but highly impactful. This page offers a summary but, for much more detail, refer to the Learn by Design Task section of this wiki which provides a highly detailed rundown of how BEM can be used to inform a plethora of design decisions throughout a design project.

Graphics illustrating typical use cases

• Common questions that can be answered with energy modeling. (Source: IBPSA-USA BEM Workshop)
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Common use cases

Energy code compliance

Determine if the proposed building complies with the energy code by comparing it's simulated energy consumption against a code-minimum version of the building. If the proposed building uses less energy, then it complies. This is a bit of an oversimplification -- read more about code compliance modeling.

Green building certification

Determine if the proposed building contributes points or credits toward green building certification by comparing it's simulated energy consumption against a code-minimum version (or similar baseline version) of the building. By reducing energy consumption of he proposed building by certain targets below the baseline, more credit can be achieved towards the green building certification. This is a bit of an oversimplification -- read more about green building and other beyond-code programs.

Research

There are numerous research-focused use cases for BEM. Researchers may use energy modeling to perform theoretical tests that might be too time consuming, costly, or impossible to perform in a lab such as analyzing product performance, analyzing simulation algorithms (e.g. testing a novel control strategy for equipment), testing large scale projects (e.g. what is the impact of applying certain efficiency or utility projects across an entire town/city/region).

Policy development

BEM plays a large role in energy policy development. When energy codes and standards are updated (typically every 3-4 years), a massive number of simulations are run to evaluate the impacts of the changes to the code. These impacts may include projected savings of a given measure (e.g. improved insulation requirements, lower lighting power allowance, etc.) on different building types in different climate zones. Savings may also be projected out to determine a statewide or national savings estimate associated with enacting the new code requirements.

Generally, many variants of a proposed code change are analyzed to assess not only cost savings, but also incremental product and maintenance costs associated with the new measure to ensure that they can be installed and maintained cost-effectively.

Other metrics are also typically analyzed including carbon impacts. More prevalent in recent years is analysis that also includes impact on the utility grids, especially when policies include renewable energy generation or battery storage requirements.

Optimize performance

Perhaps the most useful application of BEM during the design process is to use it as a design tool that helps to make good decisions - decisions that lead to improved performance in terms of energy efficiency and occupant satisfaction. As a design tool, BEM can:

• Answer questions and explore design concepts
• Identify priorities
• Gain insights
• Challenge rules of thumb
• Track performance vs. targets

Some of the questions that may be answered by these desing-focused analyses include:

What's the feasibility of...

• Natural ventilation
• Free cooling
• Passive solar heating
• Green building certification

What are potential savings from...

• Daylighting controls
• External shading

What's the impact of this design choice on...

• Energy consumption
• Energy cost
• Carbon emissions
• Thermal comfort
• HVAC equipment size
• Zero energy performance
• Required PV capacity
• Energy code compliance

The concept of BEM as a design tool is explored in great detail in the Learn by Design Task section of this wiki!