View the full story, including all images and figures, in our monthly digital edition

Back in the 1980s, when I was a computer science student, I was taught that a good systems designer would design him- or herself out of the system. This meant that the system worked, it was well documented, operators were well trained, and the system could be maintained. The system designer, like a house builder, could close the door on a project with a clear conscience and whistle while walking away, content with a job well done.

In the world of energy efficiency, there’s a word for that: persistence. Persistence is the ability of an energy conservation measure (ECM) to last—for the energy, financial, and carbon savings to accrue over time, as planned. In the parlance of systems engineering, energy engineers will round off an ECM project with persistence measures with performance benchmarks, documentation, and training.

To do anything less, engineers are shortchanging owners because the ECM won’t last long, thus undermining the integrity of any cost-benefit analyses performed that led to the ECM. It’s like selling a car without oil or transmission fluid. The owner might get the car out of the lot, but it won’t be long before the car ceases to function.

But how far should persistence measures go? The answer is that it depends on the ECM. A study by Portland Energy Conservation Inc. (PECI) and Texas A&M University on persistence of repairs stemming from commissioning buildings found that persistence has a signature: ECMs impacting the surface of systems, like thermostat setpoints and set-back schedules, were changed to accommodate immediate needs for comfort or lighting, and sometimes were not changed back to original settings. On the other hand, ECMs made deep into a system—such as trimming a pump impeller, changing control software code, or replacing a chiller—had stronger persistence. Knowing about this signature can help you with persistence planning.

Research conducted by Consulting-Specifying Engineer for the MEP Giants report on page 20 found that commissioning (Cx) and maintenance/repair/operation (MRO) services are on the rise among engineering firms. A lot of this work is energy related, as discussed in my Viewpoint last month, "There’s gold in building performance data." Engineers entering into the Cx and MRO markets need to be aware that persistence is important to building owners and program managers dispensing capital budgets and rebates. Based on the wisdom from energy conservation programs spanning 30 years, projects increasingly are requiring that ECM cost-benefit analysis include persistence measures such as documentation, training, scheduled maintenance, and ongoing/continuous Cx.

Please visit my Give and Take blog at www.csemag.com/blog , where I have posted this Viewpoint along with hyperlinks to reports and presentations on persistence that can will help you build persistence measures into your energy and environmental projects.

Send your questions and comments to: Michael.Ivanovich@reedbusiness.com

Do you have experience and expertise with the topics mentioned in this content? You should consider contributing to our WTWH Media editorial team and getting the recognition you and your company deserve. Click here to start this process.