110 research outputs found
Finding the different patterns in buildings data using bag of words representation with clustering
The understanding of the buildings operation has become a challenging task
due to the large amount of data recorded in energy efficient buildings. Still,
today the experts use visual tools for analyzing the data. In order to make the
task realistic, a method has been proposed in this paper to automatically
detect the different patterns in buildings. The K Means clustering is used to
automatically identify the ON (operational) cycles of the chiller. In the next
step the ON cycles are transformed to symbolic representation by using Symbolic
Aggregate Approximation (SAX) method. Then the SAX symbols are converted to bag
of words representation for hierarchical clustering. Moreover, the proposed
technique is applied to real life data of adsorption chiller. Additionally, the
results from the proposed method and dynamic time warping (DTW) approach are
also discussed and compared
Fault Detection and Diagnosis Encyclopedia for Building Systems:A Systematic Review
This review aims to provide an up-to-date, comprehensive, and systematic summary of fault detection and diagnosis (FDD) in building systems. The latter was performed through a defined systematic methodology with the final selection of 221 studies. This review provides insights into four topics: (1) glossary framework of the FDD processes; (2) a classification scheme using energy system terminologies as the starting point; (3) the data, code, and performance evaluation metrics used in the reviewed literature; and (4) future research outlooks. FDD is a known and well-developed field in the aerospace, energy, and automotive sector. Nevertheless, this study found that FDD for building systems is still at an early stage worldwide. This was evident through the ongoing development of algorithms for detecting and diagnosing faults in building systems and the inconsistent use of the terminologies and definitions. In addition, there was an apparent lack of data statements in the reviewed articles, which compromised the reproducibility, and thus the practical development in this field. Furthermore, as data drove the research activity, the found dataset repositories and open code are also presented in this review. Finally, all data and documentation presented in this review are open and available in a GitHub repository
A Predictive maintenance model for heterogeneous industrial refrigeration systems
The automatic assessment of the degradation state of industrial refrigeration systems is
becoming increasingly important and constitutes a key-role within predictive maintenance
approaches. Lately, data-driven methods especially became the focus of research in this
respect. As they only rely on historical data in the development phase, they offer great
advantages in terms of flexibility and generalisability by circumventing the need for specific
domain knowledge. While most scientific contributions employ methods emerging from
the field of machine learning (ML), only very few consider their applicability amongst
different heterogeneous systems. In fact, the majority of existing contributions in this field
solely apply supervised ML models, which assume the availability of labelled fault data for
each system respectively. However, this places restrictions on the overall applicability, as
data labelling is mostly conducted by humans and therefore constitutes a non-negligible
cost and time factor. Moreover, such methods assume that all considered fault types
occurred in the past, a condition that may not always be guaranteed to be satisfied.
Therefore, this dissertation proposes a predictive maintenance model for industrial
refrigeration systems by especially addressing its transferability onto different but related heterogeneous systems. In particular, it aims at solving a sub-problem known as
condition-based maintenance (CBM) to automatically assess the system’s state of degradation. To this end, the model does not only estimate how far a possible malfunction
has progressed, but also determines the fault type being present. As will be described
in greater detail throughout this dissertation, the proposed model also utilises techniques
from the field of ML but rather bypasses the strict assumptions accompanying supervised
ML. Accordingly, it assumes the data of the target system to be primarily unlabelled
while a few labelled samples are expected to be retrievable from the fault-free operational
state, which can be obtained at low cost. Yet, to enable the model’s intended functionality, it additionally employs data from only one fully labelled source dataset and, thus,
allows the benefits of data-driven approaches towards predictive maintenance to be further
exploited.
After the introduction, the dissertation at hand introduces the related concepts as
well as the terms and definitions and delimits this work from other fields of research.
Furthermore, the scope of application is further introduced and the latest scientific work
is presented. This is then followed by the explanation of the open research gap, from which
the research questions are derived. The third chapter deals with the main principles of the
model, including the mathematical notations and the individual concepts. It furthermore
delivers an overview about the variety of problems arising in this context and presents the
associated solutions from a theoretical point of view. Subsequently, the data acquisition
phase is described, addressing both the data collection procedure and the outcome of the
test cases. In addition, the considered fault characteristics are presented and compared
with the ones obtained from the related publicly available dataset. In essence, both
datasets form the basis for the model validation, as discussed in the following chapter. This
chapter then further comprises the results obtained from the model, which are compared
with the ones retrieved from several baseline models derived from the literature. This
work then closes with a summary and the conclusions drawn from the model results.
Lastly, an outlook of the presented dissertation is provide
State-of-the-Art Review and Synthesis: A Requirement-based Roadmap for Standardized Predictive Maintenance Automation Using Digital Twin Technologies
Recent digital advances have popularized predictive maintenance (PMx),
offering enhanced efficiency, automation, accuracy, cost savings, and
independence in maintenance. Yet, it continues to face numerous limitations
such as poor explainability, sample inefficiency of data-driven methods,
complexity of physics-based methods, and limited generalizability and
scalability of knowledge-based methods. This paper proposes leveraging Digital
Twins (DTs) to address these challenges and enable automated PMx adoption at
larger scales. While we argue that DTs have this transformative potential, they
have not yet reached the level of maturity needed to bridge these gaps in a
standardized way. Without a standard definition for such evolution, this
transformation lacks a solid foundation upon which to base its development.
This paper provides a requirement-based roadmap supporting standardized PMx
automation using DT technologies. A systematic approach comprising two primary
stages is presented. First, we methodically identify the Informational
Requirements (IRs) and Functional Requirements (FRs) for PMx, which serve as a
foundation from which any unified framework must emerge. Our approach to
defining and using IRs and FRs to form the backbone of any PMx DT is supported
by the track record of IRs and FRs being successfully used as blueprints in
other areas, such as for product development within the software industry.
Second, we conduct a thorough literature review spanning fields to determine
the ways in which these IRs and FRs are currently being used within DTs,
enabling us to point to the specific areas where further research is warranted
to support the progress and maturation of requirement-based PMx DTs.Comment: (1)This work has been submitted to the IEEE for possible publication.
Copyright may be transferred without notice, after which this version may no
longer be accessibl
AI-big data analytics for building automation and management systems: a survey, actual challenges and future perspectives
In theory, building automation and management systems (BAMSs) can provide all the components and functionalities required for analyzing and operating buildings. However, in reality, these systems can only ensure the control of heating ventilation and air conditioning system systems. Therefore, many other tasks are left to the operator, e.g. evaluating buildings’ performance, detecting abnormal energy consumption, identifying the changes needed to improve efficiency, ensuring the security and privacy of end-users, etc. To that end, there has been a movement for developing artificial intelligence (AI) big data analytic tools as they offer various new and tailor-made solutions that are incredibly appropriate for practical buildings’ management. Typically, they can help the operator in (i) analyzing the tons of connected equipment data; and; (ii) making intelligent, efficient, and on-time decisions to improve the buildings’ performance. This paper presents a comprehensive systematic survey on using AI-big data analytics in BAMSs. It covers various AI-based tasks, e.g. load forecasting, water management, indoor environmental quality monitoring, occupancy detection, etc. The first part of this paper adopts a well-designed taxonomy to overview existing frameworks. A comprehensive review is conducted about different aspects, including the learning process, building environment, computing platforms, and application scenario. Moving on, a critical discussion is performed to identify current challenges. The second part aims at providing the reader with insights into the real-world application of AI-big data analytics. Thus, three case studies that demonstrate the use of AI-big data analytics in BAMSs are presented, focusing on energy anomaly detection in residential and office buildings and energy and performance optimization in sports facilities. Lastly, future directions and valuable recommendations are identified to improve the performance and reliability of BAMSs in intelligent buildings
Assessment of applications of optimisation to building design and energy modelling
Buildings account for around 35% of the world’s carbon emissions and strategies to reduce carbon emissions have made much use of building energy modelling. Optimisation techniques promise new ways of achieving the most cost effective and efficient solutions more quickly and with less input from engineers and building physicists. However, there is limited research into the practical applications of these techniques to building design practice. This thesis presents the results of case-based research into the practical application of design stage optimisation and calibration methods to energy efficient building fabric and services design using building energy modelling. The application during early stage design of a Non-dominating Sorting Genetic Algorithm 2 (NSGA2) to a building energy model EnergyPlusTM. The exercise was used to determine if the application of NSGA2 yielded a significant improvement in the selection of building services technology and building fabric elements. The use of NSGA2 enabled significant (£400,000) capital cost savings without degrading the comfort or energy performance. The potential capital cost savings significantly outweighed the cost of the engineering time required to carry out the additional analysis. Three optimisation techniques were applied to three case study buildings to select appropriate model parameters to minimise the difference between modelled and measured parameters and hence calibrate the model. An heuristic approach was applied to the Institute for Life Sciences Building 1 (ILS1) at Swansea University. Latin Hypercube Monte Carlo (LHMC) was applied to the Arup building at 8 Fitzroy St London and compared directly with the results from an approach using Self Adaptive Differential Evolution (SADE). Poor Building Management System data quality was found to significantly limit the potential to calibrate models. Where robust data was available it was however found to be possible to calibrate EnergyPlus simulations of complex real world buildings using LHMC and SADE methods at levels close to that required by professional bodies
- …