Preface

The creation of this book was stimulated by the vibrant international research activity coupling energy and buildings, along with the future driving potentials and demands in these fields that will no doubt ensue. The behaviour of our buildings, both in terms of the energy they consume and the thermal comfort they provide, can be described as a function of the materials from which they are made using the underpinning principles of building physics. In terms of the outdoor environment in which these buildings are placed, we face many challenges not least of which include the predictions for significant climatic changes and greater frequency of extreme weather events. We also face future shortages of energy and clean water supply, and an expanding (and ageing) population with ever-increasing demands for the right to a comfortable, healthy living environment. It is therefore vital that all those who can contribute to tackling these issues should have access to a comprehensive summary of the current knowledge that the many experts who have contributed to this book possess. Coupled with this is the intention to help identify gaps in the current levels of understanding, and to inspire further work where it is most needed along with a broader awareness and appreciation for the wealth of inter-disciplinary fields that can make many valid contributions to one another.

There is a strong need to reduce our dependence on mechanical systems for controlling the indoor environment, especially against a background of forecasted climatic changes where cooling loads will increase whilst at the same time energy companies are less able to meet end user demands. Of course, it is vital that the exploration of better ways of meeting our energy demands (e.g. wind, tidal, geothermal, and solar technologies, etc.) be allowed to continue. However, ultimately the goal must be to achieve drastic demand-side reductions in energy, when our built environment currently accounts for around 50% of all carbon-related emissions contributing to global warming. We also have an expanding population whose average age is increasing, and who have higher expectations of health and comfort from their living environments. Any solutions to cut energy consumption will not be acceptable if they involve a backwards step in the quality of life; rather they should coincide with significant advancements. Materials and allied technologies play a vital role in tackling some of the key issues relating to operational energy efficiency and thermal comfort in buildings using measures such as:

The structure and approach of this book is to provide an integrated and comprehensive package with parts designed to support and complement each other. The first part reviews the fundamental scientific and engineering principles associated with the various aspects of building physics that relate to materials and energy efficiency. The second part focuses entirely on both conventional and advanced materials, plus material technologies whose principle applications are to improve energy efficiency and thermal comfort in buildings and other occupied spaces. The final part covers the application of advanced building materials and design across a comprehensive range of building types and classifications.

The reader can, for example, read about a particular material and/or technology in one part, whilst cross-referencing against the fundamentals that underpin its physical properties and the reasons for its behaviour, e.g. aerogel insulation materials and heat transfer in porous materials. Similarly, the reader can also read about best practice applications or a particular case study on a type of building, and cross refer this against detailed explanations of the specific materials and technologies that are employed for that application. Naturally, each chapter can also be used in isolation as a stand-alone contribution in its particular field.

Part I: ‘Fundamental issues and building physics’ begins with a large, detailed chapter by Hall and Allison covering all key aspects of fundamental heat and mass (water) transport processes in building fabrics with particular emphasis on porous materials. This is then supported by a detailed, technical chapter by Künzel and Karagiozis on hygrothermal behaviour in buildings which deals with the coupled, inter-dependent nature of heat and moisture both in terms of storage and transport within materials. The mechanisms and systems of ventilation are explained in the next chapter (by Etheridge) along with issues relating to air quality and air tightness in buildings, along with the principles and design of natural ventilation. The fundamentals of thermal storage are addressed in Chapter 4 by Wu, including the principles of psychrometrics and sensible, latent and chemical storage, along with discussion of heat storage materials and the principles of cooling. In Chapter 5, Parsons explains the principles behind the measurement and quantification of thermal comfort, including adaptive comfort responses and thermal pleasure. Finally in this part, Brimblecombe explains in detail the principles of indoor air quality and the chemistry behind indoor pollutants from off-gassing, particulates, occupant behaviour and outdoor infiltration along with environmental health and safety aspects, including indoor fire and combustion risks/hazards and toxicity.

It is widely recognised that the operational energy consumption of most building types currently outweighs their embodied energy by some margin. However, as we make dramatic increases in energy efficiency the embodied energy of the materials and components that we use will become proportionally larger and may account for a large proportion of the energy associated with buildings in the future. Along with this point is the fact that, in general terms, it is important to understand and consider the origins and manufacturing processes of the materials, as well as the energy that is required to manufacture them. For these reasons, Part II: ‘Materials and sustainable technologies’ begins with a chapter by steele that explains the principles of life cycle analysis and the approach of environmental profiling of building materials including summaries of the various energy-consuming processes upon which we rely and the environmental impacts that they can have. The following two chapters, both by Gellert, each consider insulation materials for use in buildings. The first discusses the composition, types and physical properties of various organic and inorganic mineral-based materials, whilst the second compares and explains the various types of natural fibre and fibre composite insulation materials and their performance. In Chapter 10, Feldman gives a detailed explanation of the chemical composition, manufacture and physical properties of polymeric foam insulation materials with descriptions of performance evaluation and new innovations. The following chapter by Zeitler covers thermal insulation for pipes and other building equipment and discusses the range of appropriate material types, supply forms and installations, comparison of material properties and details of regulatory performance assessment. The next topic to be covered, by Yarbrough in Chapter 12, is that of reflective materials and radiant barriers for insulation in buildings, which includes detailed coverage of the basis and approach for thermal performance assessment, regulatory codes and standards, and discussion of relevant applications and assemblies. Aerogel materials for insulation in buildings are covered in Chapter 13 by Yu, Fu and Tsang, which gives a detailed account of the processing and formation of aerogels, an explanation and discussion of their physical (including thermal) properties, and a summary of applications and future material developments. The application of hygrothermal materials for temperature and humidity control in buildings is discussed in Chapter 14 by Hall, including details of characterisation and testing of material functional properties and detailed descriptions of the various material classes and their physical properties. Chapter 15 by Warwicker follows on from this topic providing a detailed evaluation of dessicant materials, including desiccant cycles, materials class and properties, and explanations of their application for cooling and for humidity control in buildings. Phase change materials and their applications for thermal energy storage and thermal comfort in buildings are covered in Chapter 16 by Farid and Sherrif, along with case study evaluations and numerical model predictive studies. Next is a technical chapter by Zhao covering the use of porous materials for direct and indirect evaporative cooling systems and technologies in buildings with particular emphasis on novel façade technologies as well as explanations of the principles of evaporative cooling that are employed. To meet the modern demand for rapid assembly and low tolerances a resurgence of interest in pre-fabricated techniques has evolved into Modern Methods of Construction (MMC). A thorough overview of this topic is provided in Chapter 18 by Mapston and Westbrook evaluating new and emerging techniques and components and their role in improving energy efficiency and thermal comfort. Roofing materials and roof design is discussed in Chapter 19 by Jones from the perspective of improving the environmental performance and energy efficiency of buildings, whilst also evaluating material selection and thermal performance, green roofs and renewables integration. The final chapter in Part II, by Clarke and Johnstone, provides an excellent discussion on approaches to the design and environmental performance benchmarking of building fabrics by using advanced building façades as an example, and making use of relevant case studies.

Part III: ‘Application of advanced building materials and design’ begins with an intriguing and insightful overview by Watts of the major issues in balancing comfort and health with sustainability in the eco-design of buildings. The next two chapters, by Peacock and Chow, respectively, both address materials and design applications for addressing energy efficiency and thermal comfort, firstly in domestic buildings and then in commercial buildings including offices, retail spaces and warehouses. Chapter 24 by Davda, Sex and Broomfield covers in detail specific issues in balancing energy efficiency with the requirements of high performance and specialist buildings, along with strategies and approaches for achieving this in laboratories and R&D facilities, medical research facilities, as well as clean rooms and high tech industry and assembly facilities. Chapter 25 by Shao provides an informative discussion of best practice approaches and considerations in relation to energy efficiency and thermal comfort design for new buildings, since it is vital that we make significant improvements in both affordable as well as state-of-the-art housing, for which there is great and increasing demand. Of course there are many additional challenges brought about by the slow rate of renewal in our global building stock and the need to find acceptable retrofit solutions to reducing energy consumption whilst improving thermal comfort. Chapter 26 by Gillott and Spataru addresses the many issues associated with existing buildings and presents detailed discussion as to how energy efficiency and thermal comfort can be enhanced in line with modern best practice standards using materials and allied technologies for building retrofit. Finally, due to the wide variety in climatic regions across the globe, the last chapter, by Gadi, addresses how material selection and its incorporation within building design can be used to work with, rather than against, the ambient conditions found in different climatic zones in order to provide both energy efficiency and thermal comfort.

It is hoped that this book will give great pleasure to many readers around the world and will prove to be a useful and informative resource for learning and instruction to students within the field. In addition, it is intended that this book will also act as a comprehensive and useful point of reference for researchers, academics, architects and engineers, and the industry, to maintain an awareness of the current state of knowledge and understanding, to give ideas and inspiration for new work in need of attention, and to develop a mutual appreciation for the many disciplines that can work together in the name of progress.