Evaluation of Retrocommissioning Persistence in Large Commercial Buildings

Commercial Building Retrocommissioning activity has increased in recent years. This paper discusses LBNL's recently conducted study of 8 participants in the Sacramento Municipal Utility District Retrocommissioning program. We evaluated the persistence of energy savings and measure implementation, in an effort to identify and understand factors that can improve the longevity of retrocommissioning benefits. The LBNL analysis included a whole-building and measure status analysis, incorporating elements of previous work by Texas A&M University and Portland Energy Conservation Inc. Included in the energy analysis were whole building calculated energy savings and consideration of effects from the 2001 energy crisis. The measure persistence analysis examined each recommended measure and it's current operational status. Results showed a 59% implementation rate of recommended measures. Some process findings were: - Building engineers will tweak a measure that didn't work, instead of reverting to the pre-retrocommissioning settings - A majority of the implementation costs were absorbed into regular operation and maintenance budgets - The most frequently reported down side was the large time demands on the building engineering staff. However, all respondents thought it was worth the price. - All the sites said that retrocommissioning is beneficial to their operations, due to on-going training and continuous improvement of system specifications - Approximately 65% of the peak retrocommissioning savings persisted beyond four years