RetroCommissioning - what's typically discovered

Many case studies of existing building commissioning efforts have been published over the years. A review of case studies for multiple buildings published by Portland Energy Conservation, Inc. (PECI), Texas A&M University, proceedings from National Building Commissioning Conferences, and FEMP Assessments of Load and Energy Reduction Techniques (ALERT) is useful in identifying measures most typically available in commercial building spaces. The most frequently cited retrocommissioning measures/opportunities are:

 

  • Adjust reset and set-back temperatures and temperature settings – Settings are often adjusted over ime based on personal preferences, to compensate for inadequate system operation, or to achieve nergy savings. In addition, sensors require periodic recalibration.

  • Staging/sequencing of boilers, chillers, and air handling units – Equipment should be operated in he most efficient combination of chillers, boilers, and fans at varying load conditions.

  • Adjust and repair dampers and economizers – Malfunctioning or poorly tuned dampers (including seals, actuators, and linkages) and economizers result in (1) increased supply air fan energy in the closed position or require additional air heating and cooling when open too much, (2) undesired building operating conditions due to lack of outside air, and (3) premature equipment degradation and replacement.

  • Modify control strategies for standard hours of operation – Motors, pumps, fans, and air handlers often operate on a 24/7 schedule even though not required by either the building tenants or the building operating plan.

  • Eliminate simultaneous heating and cooling – Heating and cooling systems for the same space can compete against each other due to improper setpoints.

  • Air and water distribution balancing and adjustments – Systems require rebalancing due to drift and changing building/workspace mission and/or tenant requirements.

  • Verify controls and control sequencing including enabling and re-enabling automatic controls for setpoints, weekends, and holidays. Verify that overrides are released.


From the DOE FEMP Operations and Maintenance Best Practices Guide: Chapter 7: Commissioning Existing Buildings,