Second law efficiency and the relative free energy function

Abstract:

A new definition of second law efficiency for productive thermal systems is proposed in this paper. The very root of the idea is that efficiency should be a quality index of the system. This implies that second law efficiency must be a homogeneous function of zero order with respect to quantity. To accomplish this, both products and fuels (resources) must be defined in such a manner that a strict separation between `quantity' and `quality' is needed. Also as a consequence, a new thermodynamic function is systematically obtained: b≡h-Txs where Tx is defined as the variation of enthalpy with respect to entropy when an additional entropy generation occurs in the system that interacts with this flow. i.e. Tx≡(dh/ds)δSg. Several simple cases are shown and a general method is given to obtain the relationship for this definition of efficiency for any productive system.

Año de publicación:

1992

Keywords:

Fuente:

scopus