A Utility-Sponsored Incentive Program for Monitoring Based Commissioning of Existing Buildings Using FDD Toolsets
Greg Cunningham and Randy Despain
Enovity’s Monitoring-Based Persistence Commissioning (MBPCx) Program for existing buildings is a utility-sponsored program targeting energy efficiency measures in large commercial buildings through building tune-ups and control systems optimization, with a persistence component delivered through continuous or extended monitoring of building performance. MBPCx is currently offered as a Pilot Program under PG&E's 2006-2008 Energy Efficiency offerings.
There is general consensus that retro-commissioning offers potential for cost effective optimization of HVAC systems. While energy focused retro-commissioning programs have produced significant savings, results from a recent industry study suggest there is a likelihood that savings may degrade within a few years due to factors that include O&M staff turnover, changes to the control system without an understanding or knowledge of the retro-commissioning recommendations, lax preventive maintenance, and equipmnent failure, among others.
Through Enovity’s MBPCx Program, monitoring-based fault detection and diagnostic (FDD) software tools have been installed at customer sites to identify additional deficiencies not found during the traditional retro-commissioning process, to monitor system performance, to report when a sequence is changed or over-ridden, and to generate reports regularly to identify new or recurring system faults. With FDD reporting, operators can identify and correct problems quickly, maintaining energy savings and operational benefits. FDD tools may also facilitate measure verification, an important component of utility-funded energy incentive programs.
This paper will outline Enovity’s work on MBPCx Program development and implementation, and will discuss program goals and process, tools employed, challenges encountered, and lessons learned to date. We will also report on preliminary results from one or more program sites.
Fault Detection and Diagnostic Tools Donald J. Frey, P.E.
This presentation will discuss the application for Architectural Energy Corporation’s ENFORMA® Building Diagnostics™ (EBD) to assist with identification of problems with the operation of the HVAC equipment at the St. Regis Hotel in downtown San Francisco. It will also address the value this tool provided and how persistence will be enhanced.
Retrocommissioning of the St. Regis was done under the Retrocommissioning Services and Incentives program sponsored by Pacific Gas and Electric and managed by PECI. EBD operates on the Tridium NiagaraAX platform. The St. Regis has an Invensys energy management system (EMS), which is also Tridium based. This simplified the process of extracting data from the EMS and transferring it to AEC’s Tridium server. EBD’s web-based format also made it possible for anyone to access the data and results from a password-protected website.
EBD uncovered problems with the operation of the building that would not have otherwise been identified or quantified as precisely during a typical retrocommissioning investigation process, including frequent oscillations between economizer to mechanical cooling mode in one of the air handlers and frequent changes between high and low exhaust in a humidity-controlled exhaust fan. The application also revealed the chilled water valve was open during economizer cooling and the cooling coil in the main air handler was not being controlled to maintain a constant supply air temperature. EBD shows the frequency at which all of these problems occur and quantifies the percentage of time that operation is faulty. The result was that a more comprehensive investigation was performed than could typically be performed within a utility incentive-based retrocommissioning process. Once the measures are implemented, the system will be used to verify that they are working properly and to track their persistence. EBD also minimizes the variation in approach and thoroughness from one engineer to another during the investigation process. The ultimate benefit is more savings that persists longer.
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