Glossary Glossary of principal symbols A, A class A j A s j A C A k A n (x n , u n , t n , Â n ) a i a v b g , b s b v C, c c v c m c 0 D E E e F F, F F F k F n (x n , ) f n (x n ) f 0 , f i Energy Optimization in Process Systems Copyright © 2009 Elsevier Ltd. All rights reserved. generalized and classical exergy (J, J m -3 , kJ kg -1 ) chemical or electrochemical affinity of jth reaction (J mol -1 ) affinity of jth reaction in the entropy representation (J mol -1 K -1 ) - G chemical affinity at Carnot point (J mol -1 ) total exchange area at stage k (m 2 ) criterion of stage optimality activity of ith species (mol m -3 ) specific area per unit volume (m -1 ) specific exergy of gas and gas in equilibrium with solid (kJ kg -1 ) exergy per unit volume (kJ m -3 ) unit prices of controlled and controlling phase, repectively ($ kg -1 ) specific heat per unit volume (J m -3 K -1 ) mass capacity of active component of fuel (J -1 ) propagation speed of thermal waves (m s -1 ) diameter (m -1 ), diffusion coefficient (m 2 s -1 ), profit ($), disorder (­) electric field vector (kg m A -1 s -3 ) total energy or energy type function (J) unit energy (J kg -1 ), economic value of unit exergy ($ J -1 ) force (N), specific external force (N kg -1 ), vector of potentials free energy and extended free energy, respectively (J) area of surface perpendicular to flux direction (m 2 ) potentials or components of vector F = (T -1 , - 1 T -1 , ..., - n T -1 ) optimal drying function at stage n (kJ kg -1 ) optimal performance function of a dynamic programming algorithm intensity of generalized profit and process rates