NBI Collaborates with CIEE on Two Measured Performance Case Studies

In collaboration with the California Institute for Energy and the Environment (CIEE), NBI recently completed measured performance case studies for two buildings on the University of California campus at Merced (UCM). Classroom & Office Building Case Study
Science & Engineering Building 1 Case Study We expected it to be a relatively straightforward project, to be completed in just a few months. The buildings had already been occupied for a year, and we’d simply need to request the measured whole building energy and peak power results for comparison with the targets established when the campus was being designed, then use a site visit and interviews to identify key strategies used to achieve results and lessons learned for future improvement. A readable 4-8 page synopsis would then communicate these results and provide a model for others to follow in openly documenting performance in a way that would benefit the entire green building community.

Over 18 months later, with much help from the initial project team and LBNL for data analysis, we’re happy to present the case studies. They show commendable results in exceeding the initial performance targets for these buildings – and in going the extra mile to gather, use and share measured performance results. But why did it take so long for these case studies to emerge? That story is also instructive for what it tells us about the general process of reviewing performance.

Much of the extra time needed for the UCM studies was because of the need to credibly allocate campus central plant energy use to each building. This challenge doesn’t apply to most commercial buildings, although there are certainly lessons that could be applied to any district energy development. Although monitoring was anticipated from the outset, meter failures and the lack of a data acquisition system that could easily link to Energy Information System software meant that our final numbers came from version 14 of an 8 megabyte spreadsheet which linked to many further detailed underlying tables. Without the skills of CIEE and Lawrence Berkeley National Laboratory (LBNL) in energy data analysis, the information would never have come together. At this stage, NBI provided third part review of methodologies, approximation methods where needed to fill data gaps, and the reasonability of overall results. Key process lessons include:

  • Install meters at the key points to measure to be able to evaluate your results, starting with the whole building by fuel and adding submeters as appropriate for the building’s size and complexity.
  • Commission meters, submeters, and monitoring systems up front.
  • Plan and construct to facilitate using Energy Information Software to easily provide up-to-date overviews of recent and historic performance.
  • Pay attention to accuracy. “Measured” results that are materially wrong are obviously not helpful. BUT –
  • Don’t insist on perfection. Timely, early measured performance is incredibly useful in “tuning” a new building as well as ongoing performance maintenance and improvement. Estimates to replace gaps or unreasonable measurements are fine as long as they are clearly recognized, documented, and used as an initial baseline to which future more complete results can be compared. We learn from our experience, including the experience of where measurements don’t appear to be working.
  • And finally, communicate your results: internally to improve the current building, to management to guide the organization’s future construction, and to your design team and the building community at large to help them improve their future projects.