In order to function, a turbine requires a suitable working fluid, a source of high grade energy and a sink for low grade energy. When the fluid flows through the turbine, part of the energy content is continuously extracted and converted into useful mechanical work. Steam and gas turbines use heat energy, while water turbines use pressure energy. The main objectives of the turbine designer are to ensure that this process is carried out with 'maximum efficiency' by means of plant having 'maximum reliability' at 'minimum cost'. Second objectives are that the plant should require 'minimum supervision' and 'minimum starting time'.
These five objectives conflict with each other and the final outcome will be an acceptable compromise between them.
Chapters 1 and 2 outline modern power station practice as implemented by UK turbine makers. The reasons behind every facet of turbine development are explained and, where necessary, technical terms are defined quantitatively and qualitatively to emphasise standard practice.