Maintenance of Smart Buildings using Fault Trees

TL;DR

This paper presents a framework that uses Fault Maintenance Trees encoded into Continuous Time Markov Chains to evaluate dependability and maintenance costs in smart building systems, demonstrated on HVAC systems.

Contribution

It introduces a novel method for encoding Fault Maintenance Trees into CTMCs for dependability analysis of smart building systems.

Findings

Effective evaluation of dependability metrics

Comparison of maintenance strategies for HVAC systems

Quantitative analysis of maintenance costs

Abstract

Timely maintenance is an important means of increasing system dependability and life span. Fault Maintenance trees (FMTs) are an innovative framework incorporating both maintenance strategies and degradation models and serve as a good planning platform for balancing total costs (operational and maintenance) with dependability of a system. In this work, we apply the FMT formalism to a {Smart Building} application and propose a framework that efficiently encodes the FMT into Continuous Time Markov Chains. This allows us to obtain system dependability metrics such as system reliability and mean time to failure, as well as costs of maintenance and failures over time, for different maintenance policies. We illustrate the pertinence of our approach by evaluating various dependability metrics and maintenance strategies of a Heating, Ventilation and Air-Conditioning system.