District heating and cooling for energy conservation

workers. Now, people from many backgrounds have joined the quest for buildings which are not only ‘energy efficient’ but also environmentally comfortable throughout the year. Legislation such as Parts F and FF of the Building Regulations and the new Parts Q and R go part of the way towards reducing the energy consumption of buildings but their effectiveness in securing acceptable internal conditions is minimal. In this book, the authors have drawn together discussions of the factors which are important in ‘good’ building design, namely, the fabric and services of the building and i ts overall thermal performance in relation to human thermal comfort. The individual chapters are nonetheless essentially self-contained which may be advantageous to the student who is learning the subject in stages. The building designer however would probably wish to see more discussion of the interactions between the various factors outlined above and of the close interdependence of design decisions. The book begins with a discussion of the fundamental concepts of heat, temperature and the mechanisms by which heat is transferred. The various parameters which are used a t later stages in the book such as U-values and environmental temperature are introduced and in each case their estimation is explained from first principles. The subject of human thermal comfort is obviously of prime importance in any text on buildings since human requirements dictate that buildings must be conditioned to provide acceptable internal conditions. The authors have reviewed the work of Fanger and Bedford, amongst others, but have given little consideration to the adaptability of occupants. In the context of energy conservation, greater emphasis should perhaps be placed upon this ability to adapt since constraints often result in the non-achievement of ideal comfort conditions. Such constraints include, for example, statutory ‘maximum legal heating limits’ or a commitment to regulate a building by natural means during the summertime. Atmospheric contaminants arising from various sources, in particular building materials, and their method of removal are of topical interest and the authors have summarised the findings of recent research work in this area. I t is worth noting that the referencing of each of the seven chapters of this book is extremely good and provides extensive lists for further reading. Various sections of the CIBS Guide and several digests of the Building Research Establishment form the basis for the chapter dealing with steady state heat transfer. I t is not clear why the authors have chosen to develop a calculation method which considers heat losses via air and environmental points quite separately and then incorporates the effects of different types of heating. The CIBS Guide procedure is much simpler and allows for all of these factors in a single equation. A brief summary of the thermal insulation materials currently available, in particular their thermal properties, applications and positioning in relation to condensation risks provides a useful conclusion to this chapter. The title of the following chapter, ‘Temperature Regulation Systems’ hides the fact that this section deals not only with temperature regulation by heating and cooling services but also by the building itself. I t is the latter perhaps which is the real key to energy conservation in buildings and in their discussion, the authors have identified the factors which must be considered to achieve optimum performance in this area. Various types of heating, cooling and humidity regulation systems are reviewed and attention is drawn to the importance of the positioning of equipment. The discussion of equipment is continued in relation to the dynamic performance of both building and plant.