As the building industry has improved the energy-efficient performance of equipment, it has become apparent that effective commissioning and maintenance of building systems and equipment is needed.
According to the Energy Systems Laboratory at Texas A&M University, considered to be an authority of ongoing or continuous commissioning, implementing an effective program reduces total energy consumption and related costs by 15 to 45 percent. In addition, it extends equipment life, improves or maintains occupant comfort, and improves equipment availability.
Ongoing commissioning, according to Lia Webster, senior engineer, Portland Energy Conservation Inc. (PECI), tracks and maintains building operations.
“The process keeps operational documentation current, ensures that staff is consistently trained and identifies new opportunities for improving building operations,” she said.
The recommissioning process includes several steps. The original commissioning documents are referenced for the established performance baseline of the building. That means the building must be commissioned in the first place.
“If there is no established baseline, the commissioning authority would test the systems against design documents,” said Darek Bombala, vice president of operations, TMCx Solutions, Solona Beach, Calif.
Mechanical, electrical, plumbing and life safety systems are typically commissioned. Problems most amenable to ongoing commissioning, according to Oregon-based PECI, include diagnosing malfunctioning sensors, valves, dampers or actuators and faulty or improper ventilation control strategies. Specific electrical commissioning activities may focus on lighting, photovoltaic systems, emergency generators, automatic transfer switches, electrical metering, uninterruptible power supplies and batteries, and power distribution.
“The commissioning authority can use the building automation system [BAS] to verify the sequence of operations and to monitor and analyze system data trends,” Bombala said.
The goal of implementing an ongoing commissioning plan is to maintain the original energy savings and keep those processes in place and operating properly as well as to identify additional improvements, Webster said.
“Studies show that the energy savings from the original commissioning degrade over time, and an ongoing commissioning process helps the owner protect its long-term investment,” she said.
Often, the primary driver for performing ongoing commissioning is energy savings. Others include smoother building operations, the development of a standard method to investigate system operations, improved building documentation, trained staff, lowered maintenance and operations costs, verification that the building is operating as designed, and occupant satisfaction. The data collected can also be used to make informed decisions when upgrades to the electrical and mechanical systems are implemented.
The BAS is typically the fundamental tool used to investigate how building systems are operating and to identify energy-efficiency opportunities.
“If the BAS is insufficiently robust to gather the necessary information, data loggers, with which electrical contractors are already familiar, can be used to fill in the data gap,” Webster said.
Contractors can also use functional testers and other handheld tools, such as infrared cameras, to identify energy-efficiency opportunities or systems anomalies throughout the building.
“The heart of ongoing commissioning is the investigation. Once that is completed and the opportunities for improved efficiency are identified and the changes are implemented, the ongoing commissioning process really begins,” Webster said.
Although Webster believes trained engineers should perform ongoing commissioning activities because identifying energy savings can be nuanced, she also believes electrical contractors could do it.
“Ongoing commissioning can be broken down into performance tracking, updating documentation, ongoing training and periodic recommissioning,” Webster said.
Since performance tracking is really monitoring system performance and using that information to detect and solve problems, contractors are in an excellent position to provide that information and offer potential energy savings solutions to the building owner.
“The energy consumption data is made meaningful by comparing it to the expected load profile, and if those performance requirements aren’t met, the contractor can use its system expertise to determine the cause,” Webster said.
There are software packages available for both building owners and ECs that monitor energy use and automate the detection of performance anomalies.
A contractor also can help an owner plan ahead for tracking the building’s energy use.
“For example, installing meters in key places is an excellent way to monitor entire systems and subsystems separately. That data is incredibly helpful in controlling energy costs and is a value add to both the contractor and building owner,” Webster said.
BREMER, a freelance writer based in Solomons, Md., contributes frequently to ELECTRICAL CONTRACTOR. She can be reached at 410.394.6966 and firstname.lastname@example.org.