Exergy Values of the Elements

The following example for graphite illustrates how the chemical exergy value for all other elements can now be calculated (Table 7.3). For the calculation of 

Standard Chemical Exergy Values at P0/ T0 of Various Components Present in Air 

Source Szargut, J. et alv Exergy Analysis of Thermal, Chemical, and Metallurgical Process, Hemisphere Publishing Corp., New York, 1988. 

of graphite, we make use of the reaction in which C02 is formed from the elements in their stable modification at P0, T0  

The corresponding change in standard Gibbs energy is called the standard Gibbs energy of formation of C02, A/G298.i5, and is defined as 

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For the remaining elements, reference compounds have been chosen, as they occur in seawater or in the lithosphere, the earth s crust. An important aspect of this choice has been that the calculated exergy values of most compounds should be positive. Table 7.3 lists the standard chemical exergy values of the elements as presented in Szargut s well-known standard work [1]. Chapter 8 gives an example, the adiabatic combustion of H2, to illustrate the use of these exergy values in an interesting application. 

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