Efficient Building Operation Research Articles

Indoor occupancy estimation using the LTE-CommSense system

ABSTRACT Indoor occupancy estimation is necessary for the efficient operation of smart buildings. The development of an efficient algorithm to estimate indoor occupancy will allow better control and optimization of the heating, ventilation, and air conditioning (HVAC) methods of the whole building. Various methods are proposed in the open literature, which depends on environmental sensor data, image or video data, smartphone data, and radio frequency (RF) signals. This work proposes a unique non-intrusive, low cost, passive indoor occupancy estimation solution using our novel instrumentation scheme. We call it Long-Term Evolution (LTE) communication infrastructure-based environment sensing or LTE-CommSense. It requires no signal transmission and uses LTE communication radiation using passive radar principle. Therefore, the system is less complex, has a low footprint and consumes low power requiring no regulations related to radar signal transmissions. This system uses practical data to first determine whether the indoor environment is empty or not. If not, it estimates the number of people occupying the room. Performance evaluation with practical data confirms the feasibility of this proposed approach. Consistency of this approach is verified by using data captured at different dates and times with a different set of people.

Representing Small Commercial Building Faults in EnergyPlus, Part I: Model Development

Small commercial buildings (those with less than approximately 1000 m2 of total floor area) often do not have access to cost-effective automated fault detection and diagnosis (AFDD) tools for maintaining efficient building operations. AFDD tools based on machine-learning algorithms hold promise for lowering cost barriers for AFDD in small commercial buildings; however, such algorithms require access to high-quality training data that is often difficult to obtain. To fill the gap in this research area, this study covers the development (Part I) and validation (Part II) of fault models that can be used with the building energy modeling software EnergyPlus® and OpenStudio® to generate a cost-effective training data set for developing AFDD algorithms. Part I (this paper) presents a library of fault models, including detailed descriptions of each fault model structure and their implementation with EnergyPlus. This paper also discusses a case study of training data set generation, representing an actual building.

Distributed model predictive control of building energy systems coupled to geothermal fields

In building energy systems (BES), operation strategies are a key factor to exploit the full potential of renewable energy sources and thus to reduce the CO2 emission and energy costs. However, advanced operation strategies like model predictive control require high engineering effort, which limits the applicability. To ease the implementation of model predictive control in BES, we present a flexible and robust distributed control framework. The framework supports the use of different model types and timescales for the various subsystems, allowing the user to tailor models from white to black modelling according to the available system knowledge. In a case study, we apply this framework to control a real-life industrial hall. We further simulate a case in which the hall is supplied by a geothermal field to investigate the sustainable long-term control of the field. We vary the temperature setpoint of the hall and adjust the thermostats in the office rooms. Since the set temperature of the hall and offices differs, the model predictive control framework finds an economic trade-off between the requirements of those two zones. Judging from these results, the approach and our implementation could be an important contribution to energy efficient operation of buildings with renewable energy sources.

Integration of point cloud data and hyperspectral imaging as a data gathering methodology for refurbishment projects using building information modelling (BIM)

PurposeBuilding information modelling (BIM) is a digital representation of the physical and functional characteristics of a building. Its use offers a range of benefits in terms of achieving the efficient design, construction, operation and maintenance of buildings. Applying BIM at the outset of a new build project should be relatively easy. However, it is often problematic to apply BIM techniques to an existing building, for example, as part of a refurbishment project or as a tool supporting the facilities management strategy, because of inadequacies in the previous management of the dataset that characterises the facility in question. These inadequacies may include information on as built geometry and materials of construction. By the application of automated retrospective data gathering for use in BIM, such problems should be largely overcome and significant benefits in terms of efficiency gains and cost savings should be achieved.Design/methodology/approachLaser scanning can be used to collect geometrical and spatial information in the form of a 3D point cloud, and this technique is already used. However, as a point cloud representation does not contain any semantic information or geometrical context, such point cloud data must refer to external sources of data, such as building specification and construction materials, to be in used in BIM.FindingsHyperspectral imaging techniques can be applied to provide both spectral and spatial information of scenes as a set of high-resolution images. Integrating of a 3D point cloud into hyperspectral images would enable accurate identification and classification of surface materials and would also convert the 3D representation to BIM.Originality/valueThis integrated approach has been applied in other areas, for example, in crop management. The transfer of this approach to facilities management and construction would improve the efficiency and automation of the data transition from building pathology to BIM. In this study, the technological feasibility and advantages of the integration of laser scanning and hyperspectral imaging (the latter not having previously been used in the construction context in its own right) is discussed, and an example of the use of a new integration technique is presented, applied for the first time in the context of buildings.

Introduction

There is an increasing need for ensuring high energy savings throughout the building lifecycle, from the early design phases until post occupancy. Utility (services) and firmness (robustness) are principles of good design since Vitruvius, but sustainability was added as a new principle after 1980s, for a distinct understanding, evaluation and action development on energy consumption and environmental impact of buildings. Today, we are able to measure the consumption levels and environmental impact of our buildings, manage their indoor comfort, and combine this further with our personal desires. Sustainability means decreasing waste and pollution, the demand for physical resources (energy, material…) and the impact on climate change, while maintaining the indoor comfort and health conditions in a building. Design decisions for sustainability include that of land use, microclimate management, form, spatial organization, building envelope, and managing water, waste, and energy systems. The essence of sustainability lies in designing all these factors with a holistic approach, while making sure that the building is usable for the occupant. Energy efficient housing requires less energy and uses renewable energy resources in the most efficient way for the energy needed during occupancy. Kim and Rigdon (1998) define the three basic principles of sustainable design as efficient use of resources (reduce, reuse, recycle); assessment of resource consumption during construction and use; and human centered design (the interaction between the human being and the environment). This research addresses the latter, the human aspect. The buildings’ energy consumption estimated by simulation software can be validated in total, only during occupancy, when the design is tested on actual use. For residential buildings, we know that sometimes the actual energy use levels are different than the expected/calculated (Lutzenheiser, 1992; Jeeninga et al., 2001; Guerra Santin, 2010; Majcen, 2013). A couple of reasons to this can be calculation drawbacks, incorrect construction applications and unexpected occupant behavior. Therefore, better understanding of the relationship between occupant behavior and energy consumption can enable more efficient design and operation of (residential) buildings, which are more suitable to the occupants’ use considering thermal, acoustical, visual, environmental comfort, health and safety. Policy on energy efficiency in buildings focuses mostly on building characteristics and mechanical systems like heating and ventilation. Although there is strong evidence for the influence of occupant behavior on energy consumption, the effort made to gain more insight to this relationship stayed behind for a long time. This study addresses the influence of occupant behavior on energy consumption for heating and electricity use for appliances and lighting, in residential buildings. This research is conducted as a joint effort at Delft University of Technology, Faculty of Architecture, between the chair of Design Informatics; research program Computation and Performance, and the chair of Housing Quality and Process Innovation (HQPI). Chair Design Informatics, research program Computation and Performance aims to improve the performance of buildings by using computational methods for model generation and analysis, decision-making and design communication, in an interdisciplinary context. This research could contribute to the further development of computational model(s) and tools in support of user’s decision-making processes. Furthermore, one of the research goals of chair HQIP is to understand the influence of occupant behavior to energy consumption in dwellings. The PhD research of Guerra Santin (2010) and Majcen (2016) of the chair HQIP specifically focus on occupant behavior and energy consumption. This research is built partially on the same datasets as Guerra Santin (‘OTB dataset’ and ‘WoON survey’), with different research questions. Findings of Guerra Santin and Majcen’s research are referred to, in the relevant sections of this thesis. Most of the research conducted under the title of this PhD was published between 2009 and 2013.

Realising Operational Energy Performance in Non-Domestic Buildings: Lessons Learnt from Initiatives Applied in Cambridge

The gap between the intended and actual energy performance of buildings is increasingly well documented in the non-domestic building sector. Recognition of this issue has led to the availability of a large range of initiatives that seek to ensure energy efficient building operation. This article reviews the practical implementation of three such initiatives in a case study building at the University of Cambridge. The notionally high-performance office/laboratory building implemented two voluntary design frameworks during building planning and construction: the voluntary rating scheme BREEAM and a bespoke Soft Landings framework called the Cambridge Work Plan. The building additionally meets the energy reporting criteria for the EU Energy Performance of Buildings Directive (EPBD), a legislative requirement for many publicly owned buildings in the UK. The relative impact of these three approaches for optimising building energy performance is reviewed through a mixed methods approach of building occupant and operator interviews, document analysis and energy performance review. The building’s core functions were revealed to consume 140% more energy than the building logbook estimate for the same needs. This difference, referred to widely as the energy performance gap, is larger than the majority of reported UK university buildings in the energy reporting database CarbonBuzz. The three implemented initiatives are demonstrated to be inadequate for reducing the energy performance gap in the case study, thus a number of alternative energy efficiency approaches are additionally reviewed. Common to the three approaches used in the case study is a lack of verification of actual building performance despite ambitious sustainability targets, due to a heavy focus on the design-stage and few follow-up mechanisms. The paper demonstrates the potential of energy efficiency initiatives that are focussed on operational performance as a core criterion (such as the Living Building Challenge) together with those that ensure the creation of realistic energy estimates at the design stage (such as the Chartered Institution of Building Services Engineers (CIBSE) Technical Memorandum 54).

An Analysis of BIM Web Service Requirements and Design to Support Energy Efficient Building Lifecycle

Energy Efficient Building (EEB) design, construction, and operations require the development and sharing of building information among different individuals, organizations, and computer applications. The Representational State Transfer (RESTful) Building Information Modeling (BIM) web service is a solution to enable an effective exchange of data. This paper presents an investigation into the core RESTful web service requirements needed to effectively support the EEB project lifecycle. The requirements include information exchange requirements, distributed collaboration requirements, internal data storage requirements, and partial model query requirements. We also propose a RESTful web service design model on different abstraction layers to enhance the BIM lifecycle in energy efficient building design. We have implemented a RESTful Application Program Interface (API) prototype on a mock BIMserver to demonstrate our idea. We evaluate our design by conducting a user study based on the Technology Acceptance Model (TAM). The results show that our design can enhance the efficiency of data exchange in EEB design scenarios.

Occupant centered lighting control for comfort and energy efficient building operation

We present an adaptive control strategy for lighting control in office spaces, with the aim to reduce energy consumption and provide occupant comfort. Based on the premise that each occupant is unique, yet consistent in his actions, the set-points for switching the artificial lights on and off are derived dynamically from statistical analysis of the occupancy sensor data, and from interaction with the occupant. We present a 6-week case study in 10 offices, where we achieved 37.9% and 73.2% energy savings compared to a standard setting control baseline and a worst-case scenario, respectively. We show that individual offices determine individual set-points and discuss their adaptive nature.

The indispensability of good operation & maintenance (O&M) manuals in the operation and maintenance of low carbon buildings

Increase in energy usage, particularly from fossil fuel sources is widely understood to be responsible for the environmental problems (climate change) experienced globally today. Response to mitigating this anthropogenic induced consequence created the need for innovative low carbon and renewable technologies in buildings. In the UK, government is ambitious to generate a third of her electricity from renewables by 2020; by that cutting emissions by 34% from the 1990 levels by 2020. However, it is widely acknowledged that significant differences often exist between designed and in-use performances of the buildings. Clients and end-users of these technologies appear not to be getting long term value for their investments; much attention has not been given to how these innovative technologies can be operated and maintained long into the future. Recent researches also underpin the fact that the wide information gap existing between designers and building end-users is one of the factors responsible for the performance-gap. This paper therefore presents excerpts of a research aimed at exploring a best practice approach to operability and maintainability of low-carbon-buildings. The research methodology involved the use of interviews, surveys and case study. Findings suggest that a properly prepared O&M manual is a potential document that that could bridge this gap and that it is an indispensable tool for the effective and efficient operation and maintenance of low carbon buildings.

Smart Building Technology [TC Spotlight

Smart building technology plays a key role in efficient building operation and has a close relationship with emissions reduction. A building is not only a good example for the application of automation science and engineering methods but also triggers further studies in the IEEE Robotics and Automation Society (RAS). A building is also a microgrid and, thus, provides a nice test bed for smart-grid technologies. Renewable energy systems, such as building-integrated photovoltaic panels and on-site wind power generation, will be pervasively available in commercial and residential buildings in the near future.

Decentralized cooling and dehumidification with a 3 stage LowEx heat exchanger for free reheating

This article presents the performance study of a novel decentralized ventilation system for hot and humid climates such as found in Singapore. Decentralized ventilation has a great potential for reducing pressure losses because of the short travel distances of the air. The combination of decentralized ventilation with high temperature radiant cooling offers the potential for a very energy efficient operation of buildings in hot and humid climates and to decrease their exergy destruction. Core of the ventilation system studied is a modified design of a decentralized ventilation unit incorporating a 3-stage heat exchanger. This particular heat exchanger setup ensures sufficient cooling capacity for dehumidification and offers free energy for reheating. In the process of the air treatment, the two heat exchangers’ upstream takes the roles of pre-cooling and cooling/dehumidification while the third one covers the reheating process. The results show that with the studied ventilation unit outdoor air with temperatures around 30 °C and a humidity ratio of 20 g/kg can be chilled, dehumidified and reheated such that target conditions in the supply air of 14–15 °C and 8–9 g/kg are achieved. In addition, this novel decentralized ventilation system can save around 4–5% of total cooling energy demand due to free reheating.

Multi dimensional energy monitoring, analysis and optimization system for energy efficient building operations

Abstract Monitoring, analysis and optimization of buildings’ energy consumption is of central importance for the renovation and energy-efficient operation of buildings since it allows the identification and correction of inefficient energy usage. However, the monitoring and control systems adoption for building management and control applications is hampered by the unavailability of appropriate tool environments. This paper addresses the need for integration concepts, holistic monitoring, analysis methodologies, multi dimensional decision support and scenario based control strategies through the seamless integration of ubiquitous sensing infrastructures, service oriented architectures, BIM tools and Data Warehouse technologies. The developed system is demonstrated and validated in the Environmental Research Institute (ERI) building located on the campus of National University of Ireland-University College Cork.

Sustainable Design of Reinforced Concrete Structures through CO2 Emission Optimization

AbstractEfforts are being made to achieve more efficient operation of buildings, with the goal of reducing the construction industry’s contribution to energy consumption and greenhouse gas emissions. That contribution also includes the energy embodied in structures; that is, the energy consumed in the processes of extracting, manufacturing, transporting, and installing construction materials (including recycled materials) and elements. In particular, in spite of the use of additives such as fly ash, reinforced concrete (RC) structures, which are large consumers of cement, are responsible for a sizable proportion of worldwide carbon emissions. These emissions can be reduced significantly through the more efficient use of both concrete and steel that can be achieved by optimization. Modern optimization tools are now available that make it possible to perform large volumes of calculations efficiently that are applicable to a wide variety of structural engineering problems. This study presents an optimization...

Window signalling systems: control strategies and occupant behaviour

Signalling systems that tell building occupants when to open and close windows have become a popular strategy for balancing the comfort benefits of manual windows with the efficiency benefits of automation in mixed-mode buildings. Data from surveys, interviews and site observations in 16 US buildings reveal a diversity of design objectives, control sequences and circumstances to anticipate when designing buildings with window signalling systems. The signals had the strongest influence on occupants' use of windows when they were visible, the logic behind the controls algorithms was clearly understood, and they were seen as an informational device linked to an explicit internal policy that has to do with efficient and comfortable building operation. Lower levels of participation occurred when occupants tend not to pay attention to their windows, or the signals, unless they are uncomfortable, at which point it matters little what the signals indicate. However, occupants who do discover value in the signals are more likely to be more satisfied with their personal control. Occupants' reasons for opening windows may include the desire for fresh air or air movement, which is as important to them as temperature adjustment, but admittedly difficult to program into the controls' algorithms. Les systèmes de signalisation qui indiquent aux occupants des immeubles quand ouvrir et refermer les fenêtres sont devenus une stratégie en vogue pour trouver un équilibre entre les avantages des fenêtres manuelles en termes de confort et les avantages de l'automatisation en termes d'efficacité dans les immeubles à mode mixte. Les données issues d'enquêtes, d'entretiens et d'observations sur place réalisés dans 16 immeubles des Etats-Unis révèlent une diversité d'objectifs de conception, de séquences de contrôle et de situations permettant de prévoir quand concevoir des immeubles équipés de systèmes de signalisation des fenêtres. La plus forte influence des signaux sur l'utilisation des fenêtres par les occupants a été constatée lorsqu'ils étaient visibles, que la logique sous-tendant les algorithmes de contrôle était clairement comprise et qu'ils étaient perçus comme un dispositif informationnel lié à une politique interne explicite visant à une exploitation efficace et confortable des immeubles. Des niveaux plus faibles de participation ont été obtenus lorsque les occupants avaient tendance à ne pas faire attention à leurs fenêtres, ou aux signaux, à moins qu'ils ne fussent mal à l'aise, auquel cas peu importe ce que les signaux pouvaient indiquer. Cependant, les occupants qui découvrent vraiment l'intérêt de ces signaux sont plus susceptibles d'être davantage satisfaits de leur contrôle personnel. Les raisons qu'ont les occupants d'ouvrir les fenêtres peuvent inclure le désir d'air frais ou de souffles d'air, ce qui est aussi important pour eux que le réglage de la température, mais est, il faut bien l'admettre, difficile à programmer dans les algorithmes de contrôle. Mots clés: comportement adaptatif, agence, retour d'information, mode mixte, aération naturelle, satisfaction des occupants, contrôle personnel, fenêtres

Integrated System Platform for Energy Efficient Building Operations

AbstractThe buildings provide a significant contribution to total energy consumption and CO2 emissions. Integrated monitoring, analysis, and control methodologies can reduce this by up to 30%. Howe...

Holistic system architecture for energy efficient building operation

Abstract Buildings account for almost 40% of the total energy usage and 30% of the total CO2 emissions in Europe. Environmental, legislative and economical drivers require more efficient and accurate energy management of buildings. Current building management systems do not have the capabilities of energy specific monitoring and management. In order to address these issues, in this paper, the Holistic Multi-Dimensional Information Management System will be described with its components: Data Warehouse Core, Extraction, Transformation and Loading (ETL) tool and Information Representation tools. The purpose of the developed system is to store, integrate, analyse complex data sets from multiple data and information sources such as wired/wireless sensing devices (e.g. sensor and meter readings) and Building Information Modelling (BIM) Tools (e.g. Autodesk Revit Architecture and MEP). The developed system is demonstrated and validated in the Environmental Research Institute (ERI) Building located on the campus of National University of Ireland-University College Cork.

Improving the energy performance of the built environment: The potential of virtual collaborative life cycle tools

Advances in information and communication technologies [ICTs] offer the opportunity to improve the way energy profiling tools and techniques are used to measure and inform the energy performance of buildings throughout their life cycle. The exploitation of this potential is one of the goals of a current EU FP7 funded project, entitled “IntUBE — Intelligent Use of Buildings' Energy Information”. The overall aim of the project is to improve the energy performance of new and existing buildings via the intelligent use of buildings' energy information. The main aim the energy profiling research being conducted as part of the IntUBE project is to contribute to the development of virtual collaborative ‘life cycle’ building tools to support energy efficient building design, operation and retrofit. In order to illustrate how this may be achieved this paper defines the functions of energy simulations within the IntUBE system, outlines the systems architecture necessary to those functions and presents a case study illustrating some of the functionality under development.

Integration of Different Fire Protection/Life Safety Elements into the Building Design Process

A building constitutes an integrated collection of systems that together provide a controlled environment for its occupants. And as such, in addition to the frames and foundations, such components as fire protection, mechanical, electrical, and plumbing (MEP) engineered subsystems are also a vital part of any building. Considering the variety of subsystems that make up of a building, an overall design and construction process would then require a proper planning for integration of these various subsystems into the building. Furthermore, system integration has also long been recognized as the key to an effective and efficient building operation. The integration process of a fire protection subsystem, along with MEP subsystems, within a building is quite challenging indeed and can have a profound impact on client satisfaction. This process becomes especially critical when one considers the integration of technology into the building, including the possibility for future changes in technology and plan for th...

Towards a Wireless Sensor Platform for Energy Efficient Building Operation

Currently, the IT-support for energy performance rating of buildings is insufficient. So-called IT-platforms often “built” of an ad-hoc, inconsistent combination of off-the-shelf building management components, distributed data metering equipment and several monitoring software tools. A promising approach to achieve consistent, holistic performance data management is the implementation of an integrated, modular wireless sensor platform. This paper presents an approach of how wireless sensors can be seamlessly integrated into existing and future intelligent building management systems supporting improved building performance and diagnostics with an emphasis on energy management.

Sensory pollution from bag filters, carbon filters and combinations

Used ventilation filters are a major source of sensory pollutants in air handling systems. The objective of the present study was to evaluate the net effect that different combinations of filters had on perceived air quality after 5 months of continuous filtration of outdoor suburban air. A panel of 32 subjects assessed different sets of used filters and identical sets consisting of new filters. Additionally, filter weights and pressure drops were measured at the beginning and end of the operation period. The filter sets included single EU5 and EU7 fiberglass filters, an EU7 filter protected by an upstream pre-filter (changed monthly), an EU7 filter protected by an upstream activated carbon (AC) filter, and EU7 filters with an AC filter either downstream or both upstream and downstream. In addition, two types of stand-alone combination filters were evaluated: a bag-type fiberglass filter that contained AC and a synthetic fiber cartridge filter that contained AC. Air that had passed through used filters was most acceptable for those sets in which an AC filter was used downstream of the particle filter. Comparable air quality was achieved with the stand-alone bag filter that contained AC. Furthermore, its pressure drop changed very little during the 5 months of service, and it had the added benefit of removing a large fraction of ozone from the airstream. If similar results are obtained over a wider variety of soiling conditions, such filters may be a viable solution to a long recognized problem. The present study was designed to address the emission of sensory offending pollutants from loaded ventilation filters. The goal was to find a low-polluting solution from commercially available products. The results indicate that the use of activated carbon (AC) filters downstream of fiberglass bag filters can reduce the degradation of air quality that occurs with increasing particle loading. A more practical solution, yet comparably effective, is a stand-alone particle filter that incorporates AC. In either case, further testing under a variety of conditions is recommended before making design decisions regarding the type of filters best suited to efficient building operation.