A Stair-Step Probabilistic Approach for Automatic Anomaly Detection in Building Ventilation System Operation

Emil Kjøller Alexandersen, Mathis Riber Skydt, Sebastian Skals Engelsgaard, Mads Bang, Muhyiddine Jradi, Hamid Reza Shaker*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

HVAC systems contribute to a large part of energy consumption in buildings and studies suggest that savings up to 30% can be achieved by utilising the potential of FDD methods which aim to identify faults and their root causes. In particular, model-based FDD are becoming more useful as the modelling and simulation of complex building systems have been eased due to advancements within the field. However, methods often lack the ability of effectively distinguishing between healthy and abnormal operation and some are highly subject to human evaluation. Bang et al. proposed a model-based fault detection method for automatic identification of abnormal energy performance on a daily basis in building ventilation units using a statistical definition of abnormality based on the Chernoff bound. The method enables the fault detection process to be automated which removes the need for human evaluation. However, the method is governed by linear interpolation leading to uncertain identification of abnormal operation and imprecise probability calculations, thereby triggering the need for modifications. This work upgrades the model-based fault detection method by introducing a stair-step approach to more accurately identify abnormal behaviour. The outcomes of the upgraded approach are reported for a case study building and evaluated in comparison with the original method. The improved method shows correct identification of abnormal periods and detected the precise day of a faulty occupancy counter. Moreover, it shows that the ascribed probabilities of the original approach are consequently lower for the two analysed ventilation units by an average of 13 and 15% points, respectively.

Original languageEnglish
JournalBuilding and Environment
Volume157
Pages (from-to)165-171
ISSN0360-1323
DOIs
Publication statusPublished - 15. Jun 2019

Fingerprint

Stairs
Fault detection
Ventilation
ventilation
building
anomaly
detection method
Identification (control systems)
Interpolation
Energy utilization
abnormality
interpolation
detection
method
savings
evaluation
energy consumption
energy
simulation
modeling

Keywords

  • Building performance
  • Chernoff bound
  • Fault detection and diagnostics
  • Stair-step approach
  • Ventilation systems

Cite this

Alexandersen, Emil Kjøller ; Skydt, Mathis Riber ; Engelsgaard, Sebastian Skals ; Bang, Mads ; Jradi, Muhyiddine ; Shaker, Hamid Reza. / A Stair-Step Probabilistic Approach for Automatic Anomaly Detection in Building Ventilation System Operation. In: Building and Environment. 2019 ; Vol. 157. pp. 165-171.
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abstract = "HVAC systems contribute to a large part of energy consumption in buildings and studies suggest that savings up to 30{\%} can be achieved by utilising the potential of FDD methods which aim to identify faults and their root causes. In particular, model-based FDD are becoming more useful as the modelling and simulation of complex building systems have been eased due to advancements within the field. However, methods often lack the ability of effectively distinguishing between healthy and abnormal operation and some are highly subject to human evaluation. Bang et al. proposed a model-based fault detection method for automatic identification of abnormal energy performance on a daily basis in building ventilation units using a statistical definition of abnormality based on the Chernoff bound. The method enables the fault detection process to be automated which removes the need for human evaluation. However, the method is governed by linear interpolation leading to uncertain identification of abnormal operation and imprecise probability calculations, thereby triggering the need for modifications. This work upgrades the model-based fault detection method by introducing a stair-step approach to more accurately identify abnormal behaviour. The outcomes of the upgraded approach are reported for a case study building and evaluated in comparison with the original method. The improved method shows correct identification of abnormal periods and detected the precise day of a faulty occupancy counter. Moreover, it shows that the ascribed probabilities of the original approach are consequently lower for the two analysed ventilation units by an average of 13 and 15{\%} points, respectively.",
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A Stair-Step Probabilistic Approach for Automatic Anomaly Detection in Building Ventilation System Operation. / Alexandersen, Emil Kjøller; Skydt, Mathis Riber; Engelsgaard, Sebastian Skals; Bang, Mads; Jradi, Muhyiddine; Shaker, Hamid Reza.

In: Building and Environment, Vol. 157, 15.06.2019, p. 165-171.

Research output: Contribution to journalJournal articleResearchpeer-review

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T1 - A Stair-Step Probabilistic Approach for Automatic Anomaly Detection in Building Ventilation System Operation

AU - Alexandersen, Emil Kjøller

AU - Skydt, Mathis Riber

AU - Engelsgaard, Sebastian Skals

AU - Bang, Mads

AU - Jradi, Muhyiddine

AU - Shaker, Hamid Reza

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AB - HVAC systems contribute to a large part of energy consumption in buildings and studies suggest that savings up to 30% can be achieved by utilising the potential of FDD methods which aim to identify faults and their root causes. In particular, model-based FDD are becoming more useful as the modelling and simulation of complex building systems have been eased due to advancements within the field. However, methods often lack the ability of effectively distinguishing between healthy and abnormal operation and some are highly subject to human evaluation. Bang et al. proposed a model-based fault detection method for automatic identification of abnormal energy performance on a daily basis in building ventilation units using a statistical definition of abnormality based on the Chernoff bound. The method enables the fault detection process to be automated which removes the need for human evaluation. However, the method is governed by linear interpolation leading to uncertain identification of abnormal operation and imprecise probability calculations, thereby triggering the need for modifications. This work upgrades the model-based fault detection method by introducing a stair-step approach to more accurately identify abnormal behaviour. The outcomes of the upgraded approach are reported for a case study building and evaluated in comparison with the original method. The improved method shows correct identification of abnormal periods and detected the precise day of a faulty occupancy counter. Moreover, it shows that the ascribed probabilities of the original approach are consequently lower for the two analysed ventilation units by an average of 13 and 15% points, respectively.

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