Numerical optimization in allocation, storage and recovery of thermal energy and resources 259 Taking into account the limiting value of the expression n lim n 1 - T 0 T n 1/n = ln T n T 0 we find that the limiting value of function R n (T n , ) in a quasistatic ( = 0) and reversible process (° = 1) represents the change of classical thermal exergy: R (T n , 0) = c(T n - T 0 ) - cT e ln n T n T 0 (7.62) Therefore, optimal work function (7.61) is a finite-rate exergy of the consid- ered discrete process. In the following section other functions of this kind are obtained. 7.7. LEGENDRE TRANSFORM AND ORIGINAL WORK FUNCTION