Retrocommissioning: A Persistence Study

Panel: Commercial Buildings: Program Design, Implementation, and Evaluation

Authors:
Umamaheswar Krishnan, Nexant, Inc.
Aniruddha Duttagupta, Nexant, Inc.
Alan Ahrens, CenterPoint Energy

Abstract

Retrocommissioning (RCx) projects have become more commonplace and their value is increasingly recognized by building owners, property managers, and utilities. These projects generate significant energy savings with little capital cost, thus resulting in high overall costeffectiveness. However, concerns with regards to persistence remain among some utility program managers and building owners. This paper addresses these concerns by analyzing the persistence of measures installed in 2004 and 2005 through CenterPoint Energy's RCx Program using proven Measurement and Verification (M&V) methods, where applicable, as stated in the International Performance Measurement & Verification Protocol. Projects were selected to ensure that maximum diversity is achieved with respect to market segment, measure type, and RCx service provider.

Six projects out of fourteen, that were part of the 2004 and 2005 RCx Program were chosen and pertinent data was requested and analyzed for all measures that were recommended by the RCx service providers. There were a total of forty three measures considered as part of the study. Thirty seven of these measures exhibited strong persistence, three measures were not implemented, and three measures could not be verified primarily due to logger failure, limited logging/trending potential of the system and the limited time-period at the time of the study. The results of the study indicate a demand reduction persistence of 92% while the corresponding values for energy and cost savings were 99% for those measures that were implemented.