ABSTRACT
In this chapter, we show that it is not so much energy that is consumed but its quality, that is, the extent to which it is available for work. The quality of heat is the well-known thermal ef ciency, the Carnot factor. If quality is lost, work has been consumed and lost. Lost work can be expressed in the products of ow rates and driving forces of a process. Its relation to entropy generation is established, which will allow us later to arrive at a universal relation between lost work and the driving forces in a process.
