Fundamentals of analyses of processes

A number of popular restrictions on the range of validity of thermodynamics are reviewed and found to be invalid, and the separation into first law and second law analyses of a process is discussed and shown to be unjustifiable and misleading. As a result of these reviews and discussions, we conclude that: (i) we should stop claiming that we can perform first and second law analyses separately; (ii) in every process, we should use at least both the energy and entropy balances simultaneously; and (iii) we should recognize the dynamic character of thermodynamics and the need to include in our analyses states that are not thermodynamic equilibrium. (C) 1997 Elsevier Science Ltd.