Sustaining Optimum Building Operation Using Key Metrics
Robert Austin, EMC Engineers
Sustainability of savings has become a major focus in the commissioning industry, especially in utility funded RCx projects. One key to sustaining optimum building performance is comparing predicted energy performance of a building with key measurement and verification (M&V) metrics to benchmark performance. M&V data often is used by utility companies to verify the effectiveness of large scale programs, but it is seldom used by building engineers to ensure buildings perform as intended.
This paper, presented from the perspective of an experienced RCx provider, will explore ways that M&V data can be used to ensure optimal building operation by answering key questions such as:
- Which metrics really matter?
- Can energy modeling establish key benchmarking metrics? Can reliable metrics be established when spreadsheet analysis methods are utilized?
- Do system level benchmarking metrics have adequate sensitivity to detect minor deviant operation (such as when a valve on a single air handler fails)?
- Post RCx, what common areas revert back to "sub-optimal" performance, and can benchmarking metrics be utilized to identify these issues?
- What is the best solution for preventing and addressing these areas? Should there be a more comprehensive procedure for warranty follow-up after RCx has been completed so that the RCx provider can assist in sustaining the measures as these issues arise?
Conclusions are based on case studies from large retro-commissioning projects with varying approaches over several years. The findings are equally applicable in Cx projects where determination of optimal performance parameters for future sustainability in high-performance buildings is desirable.
After the (RCx) Party is Over - Unrequited or Life-Long Savings?
David Jump, QuEST
The benefits of integrating M&V into RCx projects, particularly those sponsored under utility programs, are many. Primary among them is the establishment of an internal energy tracking system facility operators can use to maintain savings persistence. Other benefits include: establishment of a robust, transparent, and repeatable savings verification strategy, the method's diagnostic capabilities, and creation of updated energy baselines from which additional savings may be quantified. These are key elements that should be included in any RCx project that has energy savings as an objective.
Direct measurement of energy (electric, natural gas, steam, chilled and hot water) and its influencing variables (ambient temperature, operation schedules, etc.) have been applied in these projects under International Performance Measurement and Verification Protocol (IPMVP) Options B and C. This paper discusses progress and results from multiple sites, including office buildings, high-technology office buildings with data centers, and laboratories where this method has been integrated into RCx projects. It outlines the M&V Option selection criteria and method development, techniques used to collect the required data, discusses the factors determining the time period for baseline and post-installation data collection, energy modeling techniques, and other important factors.
Energy baseline models will be presented for multiple buildings. Verified savings are compared with ex ante estimated savings for several projects that have been completed. A summary of the requirements to develop on-going performance monitoring and energy tracking tools will be presented for selected facilities.
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