Changing how energy audits are done

The Rapid Energy Modeling tool quickly and comprehensively analyzes campus energy efficiency, targets inefficient buildings, benchmarks energy use and provides insights

By Matt Goss and Tim King April 9, 2020

Learning objectives

  • Learn about the conventional energy auditing practices and the drivers behind energy optimization.
  • Understand how the Rapid Energy Modeling tool accelerates the process of energy audits.
  • Look at considerations for using the REM tool.

Energy and resource optimization are often a priority for owners responsible for the operations of multiple buildings and campuses. Improving energy use within their building portfolio can help owners reach their goals, whether it be benefiting the environment, allowing them to reinvest their saved capital in other endeavors or pass savings on to customers.

Current methods for energy audits are generally expensive, time-consuming and require a high level of expertise — especially when maintaining a large and diverse portfolio of facilities. Given the large inventory of buildings and increasingly rigorous regulatory guidance, conventional energy audit methods are not scalable across large campuses. It is difficult for facility and energy managers to evaluate energy savings opportunities, assess various scenarios and return on investments and prioritize budgets effectively. As such, there’s a need to find tools that improve the energy audit process and solve these problems to achieve better, more cost-effective results for facility owners.

Previously, traditional energy audits took facility managers months to collect detailed building and system characteristics at a campus, using a variety of data sources such as spreadsheets, surveys, photos, 2D/3D plans and other information. It was also difficult to determine whether they were targeting the right buildings for retrofits, as it was often assumed that the largest buildings or those with the largest energy footprint (energy use intensity) were the ideal candidates.

An alternate approach to conventional energy auditing

Facility owners needed a more efficient way to quickly identify the best candidates for energy reduction using minimal data. Autodesk InfraWorks, an infrastructure design software, can be used as a visual and analytical platform, along with Autodesk cloud-based services to simulate and visualize the results of energy modeling to then assist with prioritizing candidates’ buildings or facilities.

Autodesk collaborated with an engineering firm to pilot an alternate approach to conduct portfolio-scale energy analyses that provides accurate energy audit results, without deploying physical resources on-site. The Rapid Energy Modeling tool, a proprietary software solution codeveloped by Autodesk and CDM Smith, can process information from numerous sources and can present information that is useful and appropriate for planning installation energy goals. Providing this level of detail ensures that practical opportunities are presented for decision-making, as comprehensive and interactive energy conservation measures’ savings are identified along with estimated implementation costs as developed with conventional construction cost-estimating tools.

Leveraging software applications

REM is a compilation of several commercial software applications with a streamlined workflow that uses the intent and strength of each unique application. The applications are standard within the industry, making them easy to learn and tailor based on client-specific goals.

As the energy analyst steps through the workflow, they can easily gather and access energy data while comparing energy conservation measures to determine peak building performance. The workflow uses three Autodesk software applications: Infraworks, Revit and Insight 360, coupled with standard cost data and proprietary Excel applications.

Infraworks serves as the central data repository, storing information on existing utility consumption and building data, including type, age, use, size, etc. Infraworks also serves as a platform to gather and visualize weather data. It allows for location (geographic information system-based) specific analyses to occur. Site-specific climate and weather data will be applied to any analyses conducted and options analyzed.

It also allows for the application of specific building geometry. Whether publicly available, constructed in real time, imported from Revit or provided through a third-party, a graphical representation of buildings will be stored and presented within the Infraworks platform.

Once data are created and/or developed and stored within the Infraworks platform, the data are communicated to Autodesk’s Insight 360 and Green Building Studio platforms. Within the Insight 360 platform, users can assess and visualize energy conservation measure impacts in real time and via scenarios compare options against calibrated baseline models. The platform allows users to evaluate and measure interactivity, for example, the effect a reduction in lighting energy has on heating and cooling.

Simulated energy consumption can then be imported back into the Infraworks platform and evaluated in several manners, including grouping facilities by EUI, to provide a graphical (color) representation of existing building performance. Once analyses are developed within Insight 360, these results can be exported into a series of proprietary analysis tools to incorporate implementation costs and conduct a series of financial evaluations. Based on the evaluations completed, graphical representations are often created to present different options for consideration.

A variable tool

REM is different from any other energy audit tools currently available. Energy audits can be performed remotely with REM because it is established on a remote assessment model, therefore improving productivity and saving up to 90% of the original time and cost it would take perform the audit traditionally. REM is completely desktop-driven, eliminating four weeks of effort from a traditional energy audit.

The software has adjustable scalability — it can apply to a single building or simulate energy consumption at large-scale campuses. REM works with minimal data; a building footprint, height, location and building type are necessary and additional characteristics are assumed based on building type using ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings or industry standards.

The tool is data-centric, running energy analyses using industry standard energy simulation engines including DOE-2 and EnergyPlus, generating millions of simulations quickly. REM can be continuously improved, so if more building or system data becomes available, it can be used to further refine the simulated outputs.

Efficient audits

The tool allows managers to perform remote energy audits of buildings, campuses and cities. It can be extremely expensive to send a team on-site to do these assessments, which can take from weeks to months. With the REM application, this can be performed remotely with minimal inputs to generate those results. This streamlines investigation of energy projects, generation of financial metrics and benchmarking, allowing owners to spend their time and money on improvement opportunities rather than the audits themselves.

Team members can be sent on-site with a better focus on the facility improvements that will provide the greatest value. This can help cities and state/federal agencies meet energy reduction requirements and goals by identifying reduction opportunities. The REM tool can also increase efficiency and reduce ownership costs.

Case study: Campus implementation

Using proprietary computer technology, CDM Smith performed REM on more than 19 buildings at a 1,900-acre installation. Comprising more than 387,000 square feet of building area, the building stock varied in age from 1918 to 2018 and served multiple purposes from maintenance, housing and administration to supply and water/wastewater treatment.

Using actual customer-supplied energy data, interactive models were developed and custom applications were written to perform interactive energy analyses on the buildings modeled and analyzed in various Autodesk tools, including Infraworks, Revit and Insight 360.The modeling was calibrated by creating a baseline scenario in Insight 360.

Once the building energy baselines were completed, four improvement scenarios were created for each of the 19 buildings on this installation in just two weeks. With consideration given for actual energy usage and consumption data, proposed upgrades consisted of upgrades to increase lighting efficiency (reduction of 0.3 watts/square foot) and upgrades to the heating, ventilation and air conditioning system (high-efficiency heat pump). A proprietary Excel macro was built to integrate RS Means, a construction estimating database and building life cycle cost programs to estimate payback. REM cut down audit time significantly and reached the same conclusion as the traditional audit.

Autodesk plans to develop customizations within the tool for clients and will continue to make enhancements, including potentially developing a client portal to view the model. The ability and affordability to leverage remotely gathering data are changing the way facility managers are looking at energy conservation, resiliency and security in the overall context of improving lives.

Author Bio: Matt Goss is a vice president and energy efficiency market leader at CDM Smith. He has nearly two decades of experience helping municipalities, agencies and other organizations increase their energy efficiency. Tim King is an architect and vice president at CDM Smith. He has 27 years of experience in architectural programming, planning, design and construction.