First steps to maintain a large fleet of building energy models

Daniel L. Villa, Joshua R. New, Mark Adams, Aaron Garrett, Gerald R. Gallegos

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations

Abstract

Continuous maintenance of large fleets of building energy models (BEMs) is a new challenge that may soon approach economic parity for large institutions as data and modeling connectivity become streamlined. In the past, BEMs have mostly been used for analyses during design with little or no reuse of the model. The Energy Independence Security Act (EISA) of 2007's requirement to complete energy and water evaluations for federal facilities is changing this. EISA requirements can be met through performance of ASHRAE energy audits that allow BEMs to be used for identifying energy savings opportunities and energy use breakdowns. Several years ago, Sandia National Laboratories (SNL) developed a fleet of 121 BEMs for site-wide energy assessments. Applications for this fleet has now been expanded to EISA compliance. The authors propose maintaining the BEM fleet on a 4-year cycle. In this process models undergo a quality check (QC) and recalibration whenever a building energy audit is performed for its corresponding building. For recalibration, auto-calibration technology is being used. This paper outlines the first year of efforts to construct a streamlined process and results for the first 5 models. The first BEM underwent both manual and auto-calibration for a direct comparison. Manual calibration incurred more cost and required more time from staff members. Auto-calibration required significantly less effort, slightly less cost, and resulted in slightly better accuracy. ASHRAE Guideline 14-2014 was met by 3 of the 5 buildings after auto-calibration. Even so, significant improvements to Normalised Mean Bias Error (NMBE) and Coefficient of Variation for Root Mean Square Error (CV(RSME)) were achieved for all five buildings. Data and model quality issues are suspected as causes for the non-compliance rather than inadequacy of the auto-calibration procedure. Many improvements to the processes used to prepare data and models have been identified including issues that require major changes to SNL's energy tracking infrastructure.

Original languageEnglish
Title of host publicationASHRAE Transactions - 2019 ASHRAE Annual Conference
PublisherASHRAE
Pages153-161
Number of pages9
ISBN (Electronic)9781947192355
StatePublished - 2019
Event2019 ASHRAE Annual Conference - Kansas City, United States
Duration: Jun 22 2019Jun 26 2019

Publication series

NameASHRAE Transactions
Volume125
ISSN (Print)0001-2505

Conference

Conference2019 ASHRAE Annual Conference
Country/TerritoryUnited States
CityKansas City
Period06/22/1906/26/19

Funding

This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the U.S. Department of Energy or the United States Government. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525. This paper has been approved by Sandia National Laboratories for unlimited release but is still subject to any applicable ASHRAE release restrictions.

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