Commissioning and Retrocommissioning: Doing it Right the First Time

Reprinted by permission from BuildingGreen.com

Making a business case for energy investments is getting easier. Equipment installed in buildings at new construction or as retrofits—such as smart utility meters, equipment controls, and building automation systems—makes it possible to cost-effectively benchmark the performance of systems and assess the impact of improvements at the building, system, and equipment levels. Hand-held instruments and data loggers can be used to make periodic measurements or to establish trends over discrete time periods to provide data where the controls can’t reach.

These tools and technologies are being applied in the field of commissioning, which has taught us that making sure a new building works properly at the start and that it is set up to work properly for a long time leads to fewer problems and reduced costs. Measurements and trending data from commissioning provides quality assurance for the construction process, and benchmarking data and documentation for assisting with recommissioning the building in the future.

Commissioning, often abbreviated as “Cx”, comes in several different flavors: In recommissioning the commissioning process is applied to buildings that were commissioned when new or retrocommissioned (RCx) at some point. Ongoing commissioning provides for regular or continuous monitoring, assessment, and maintenance of facilities.

RCx Providers and Teams

BCA guidelines define RCx providers based on their skills, encompassing everything from written and verbal communication skills to engineering knowledge; and on their hands-on experience with building systems commissioning, performance, start-up, balancing, troubleshooting, and more.

Like every other profession, there are bad, good, and great practitioners. The bad ones might simply be new or have a small subset of the skills and experience needed. Good providers have a broad range of skills and experience. Great RCx providers have all that plus an insatiable curiosity and a mastery of working with a variety of information sources on the fly, under time and other demands.

Veteran RCx provider and trainer David Sellers, P.E., senior engineer with Facility Dynamics Engineering in Portland, Oregon, put it this way explains in one of his training presentations: consider what happens when an RCx provider walks into a plant room and his or her glasses fog. It’s a bad sign if they just wipe them off and move on. It’s better if they find the source of the moisture (perhaps a steam leak) and include it on a findings report. It’s a great sign when they’ll find the leak, troubleshoot it to its cause, and then engineer a solution complete with assessments of energy and non-energy benefits.

Planning and persistence

If a Cx project is not initiated with clarity and wrapped up in such a way that fixes and improvements are perpetuated over time, it is doomed to fail.

In the planning phase, Cx providers should pay particular attention to the current facility requirements. Without them, the owner and Cx provider cannot know whether the Cx process has left the building working properly.

Steve Wiggins, associate partner at Newcome & Boyd and past president of NEBB, swears by current facility requirements and says they’re easy to create: “[They] can be as simple as a bulleted list of systems and areas in the building and descriptions of what needs to be done for each space.” He noted, “I like to use a floor plan of the facility and meet with occupants on a space-by-space basis to discuss what they need and what any special requirements are.”

That’s the start of the process. Later comes persistence—making results last. Says Santos: “Retrocommissioning providers should ask themselves, ‘What will I change so I don’t have to do this again?’ If they don’t put the answer to that question in the scope of work, then it’s not worth doing at all. The expense of making a change and not setting it up for persistence can be more expensive than not making the change at all.” Sellers puts it another way: “Several of us often joke that [without persistence measures] we save the same energy every couple of years.”

Persistence measures range from documentation of fixes and training operators to maintain them to installing automated fault-detection and diagnostics software tied into building automation systems. Strategies depend on how hard it is to track a fix, how much it costs to do so, how reliable and robust the persistence strategy is, and what the owner is willing to pay for.

Commonwealth Edison (ComEd) in Chicago, now part of Exelon, is experimenting with persistence measures in two of its retrocommissioned buildings. In one building, daily and weekly summary reports on RCx fixes are being generated by the building automation system. The RCx provider visits the facility about once a week to look at the data and talk to operators to see how things are going, making tweaks as necessary and identifying new RCx opportunities. In another building, an automated diagnostics package trends a broader range of parameters beyond the energy fixes that have been made to date, and uses software filters to look for and report potential problems. Operators within the owner’s team then make the fixes. “We want to see which of these methods provides the biggest bang for the buck,” said Ryan Stoianowski, senior program manager for retrocommissioning at ComEd.

Another persistence measure, supported by ComEd and other utilities, is mandating that at least one operator per site involved with an RCx program take an eight-class building operator certification course. “The course costs $1,250 in tuition, and we rebate $450. We are evaluating its specific impact, but we like what we’ve seen thus far,” said Stoianowski.

Dan Reese, senior program manager at Portland Energy Conservation, Inc., says that persistence approaches are often being wired into incentive programs for utilities. Customers receive incentives if they prove projects are still performing well six months to a year after being installed and commissioned.

55 West Monroe: Big Savings from RCx

The 55 West Monroe building is a 1979 multi-tenant, mixed-use 800,000 ft2 office tower located in the historic Loop section of downtown Chicago. The all-electric facility consumes approximately 13.3 million kWh per year.

An RCx effort began in 2009 with a building analysis by Servidyne, a ComEd-approved RCx service provider, in collaboration with building managers and engineering staff from building manager Jones Lang LaSalle. Energy-saving opportunities that were implemented included:

  • Optimizing supply and return fans on main air handler.
  • Refining the night setback scheduling capability by zone for the perimeter baseboard electric heating system.
  • Optimizing supply air temperature.
  • Resetting the chilled water temperature.

These measures are providing electrical savings of 760,000 kWh annually, with a monthly peak demand reduction of 26 kW and annual energy cost savings of $64,000. A ComEd incentive of about $75,000 dropped the owner cost of the project to $28,300 for a simple payback of just over five months.

Analysis at the meter level shows that whole-building energy consumption is down 14% compared to the same period the previous year (after correcting for weather differences and occupancy changes). Dramatic savings are occurring at the air handlers, where meters show energy consumption is down 31%.

Excerpted from the BuildingGreen.com article by Michael Ivanovich “Retrocommissioning: Big Savings for Big Buildings.” The full article, including a list of the best free online Commissioning and Retrocommissioning resources, is available online here: http://www.buildinggreen.com/auth/article.cfm/2010/9/29/Retrocommissioning-Big-Savings-for-Big-Buildings