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Six Tools for Tracking Energy Performance
How’s your building running? As a property manager, energy manager, or facility engineer, when a colleague or building owner asks you that question, what comes to mind? The frequency of comfort-related occupant complaints (or compliments)? What about how the building’s systems are working, preventive maintenance, or energy consumption?
The answer is probably based on a comparison to your building’s peers, past performance, or goals. As options for building rating systems and tracking tools multiply, the commercial building industry is placing an increasing emphasis on performance.
You can find the answers to your questions by tracking key metrics and making comparisons, or you can rely on a gut feeling of how well your building runs.
Why Track Performance?
Building owners and energy managers find value in tracking the performance of their facilities. They monitor performance in order to:
- Maintain occupant satisfaction
- Reduce operating costs and enhance property value
- Be positioned as an industry leader through green rating systems such as ENERGY STAR and LEED
- Protect against liability issues, such as poor indoor air quality
- Increase confidence in long-term savings from energy projects
- Meet corporate sustainability goals
Performance Tracking Tools
Software tools are a vital component of any performance tracking program. Buildings generate two rich streams of performance data: energy use (the building’s energy consumption) and system performance (how well each building system functions). Utilizing these data sources to achieve optimal occupant comfort with the least possible energy consumption typically requires integration of an energy tracking tool with a system tracking tool.
Within these two broad categories are six more specific categories (see graph):
Benchmarking and utility bill analysis tools periodically track overall building energy performance. ENERGY STAR’s Portfolio Manager is an example of a basic energy tracking tool. Facilities that track their ENERGY STAR score on an ongoing basis are doing two things:
- Comparing their current energy performance to others in the U.S. For buildings that have a high score, this can be a valuable marketing tool to help attract and retain tenants.
- Comparing their current energy performance to their past performance. This can help illustrate drifting energy performance and demonstrate the impact of energy retrofit projects and other changes.
When energy performance drifts – as evidenced by a reduced ENERGY STAR score, for example – the building automation system (BAS) can identify the specific cause. Used in combination, ENERGY STAR’s Portfolio Manager and the BAS are a popular and powerful set of tools for monitoring performance that create a strong foundation for any performance tracking program.
Moving up a level in complexity, energy information systems (EIS) are software systems that store, analyze, and display current and historical energy use. They typically monitor hourly power usage. The user must review the charts to look for unexpected anomalies to compare to how the data should look.
Building automation system metrics give a more detailed view of system performance than an EIS. There are thousands of BAS points you could monitor, but you can also limit the scope to a subset of key performance indicators that provide a more generalized health check. A metric combines multiple BAS points to provide deeper meaning than an individual point and can be tracked against historical or expected values. Tracking metrics requires an operator to review the data and compare it to an established baseline.
Advanced EIS tools go beyond the capabilities of less complex EIS tools. They can predict expected energy use based on weather and other variables and alert the user if energy consumption exceeds that prediction. The energy use prediction is based on models that incorporate recent energy use and current operating conditions. An advanced EIS reduces the need for manual judgment and may identify problems that are subtler than what a less complex EIS setup would show.
Fault detection and diagnostic tools (FDD) typically use performance data from the BAS to automatically generate an alarm when any system being monitored breaks preset rules, known as “expert rules.” These rules go far beyond simple temperature and pressure setpoint limits to identify subtle, interactive faults. For example, you might set a rule that the system must generate an alarm if a particular supply fan runs for two minutes and the command to the fan is off.
A Process of Continuous Improvement
Building owners and managers are fortunate to have a wide array of tools available to support continuous performance improvement. It is critical to understand, however, that tools alone are not effective unless they are part of a strong management framework that also encompasses people and processes.
FMs must be knowledgeable about the performance tracking process, and the type of performance data being tracked must suit their needs. The performance tracking team should establish specific goals and clearly defined accountability. The process should follow a continuous improvement cycle that includes four main steps:
- Collect data and track performance. This can include data from both energy and system tracking tools.
- Detect performance issues. This process can be done either manually or automatically using tools that present information in a useful way.
- Diagnose issues and identify solutions. Energy tracking tools typically show when the building’s energy performance is beginning to drift, but not why it’s drifting. Systems tracking tools, such as the BAS, can help the performance tracking team identify specific issues and determine corrective action.
- Fix issues and verify results. A tracking program is useless if it does not include a well-defined process for fixing issues.
Each of these steps is important for a successful program. By repeating these steps, building owners can ensure continued improvement. It’s often said that “you can’t manage what you don’t measure.” Tracking tools provide the measurement while the framework guides the management.
Which Approach Is Best for Your Building?
The best approach depends on your specific goals and the capabilities of your team. Keep these principles in mind as you implement your tracking program:
- Purchase tools that will be used frequently. Many industry leaders have found success through simple low-cost tools. A user-friendly toolbox, well-trained staff members, and effective processes are far more valuable than sophisticated tools without a solid framework for utilizing them.
- Start where you are and build upon success. Consider the needs and capabilities of the facility staff, from the boardroom to the mechanical room, when selecting a tool and developing a process.
- Use additional resources to help get started. Energy consultants, commissioning providers, and performance tracking tool vendors are often good resources.
The recurring message from commercial real estate leaders who have invested in building performance tracking is that it quickly pays for itself through reduced energy costs and improved comfort for occupants. And these leaders know just what to say when someone asks “How’s your building running?”
The California Commissioning Collaborative recently completed The Building Performance Tracking Handbook: Continuous Improvement for Every Building, along with four case studies from leading public and private sector owners. These are available for free at tinyurl.com/BPT-Handbook.
Dave Moser, PE, is a senior engineer at PECI providing engineering services for a range of building energy efficiency projects. His experience includes the technical aspects of utility building commissioning programs, in-building commissioning projects, and research. Eliot Crowe is a senior program manager with over 16 years of engineering and project management experience.