Exergy Cost Calculation and Cumulative Energy Indices

Exergy Components: Fuel, Product, and Irreversibility

• Fuel (F): The total exergy (valuable energy) resources consumed by a specific component to perform its function.
• Product (P): The useful, high-quality energy output generated by that component.
• Irreversibility (I): The internal energy wasted or destroyed inside the component due to inefficiencies such as friction or heat loss.

Exergy Cost Calculation Algorithm

For the known exergy efficiency of particular components of the system, the algorithm for exergy cost calculation is presented below.

Incidence Matrix and Matrix Formulation

To determine the incidence matrix for the presented system and calculate the exergy cost of the flows, a mathematical matrix structure is implemented:

Incidence Matrix (A): An incidence matrix, or connection matrix, is defined to trace and organize all the connections between the individual components of the system. Rows (i) represent the elements or components of the system, and columns (j) represent the exergy flows.

Conservation Law and Balance Equations

The Conservation Law Matrix Equation: The structural cost equations are compiled based on the exergy cost balance conservation law. A set of balance equations is utilized for the calculation of the cumulative indices.

Cumulative Energy and Exergy Consumption

Examples of cumulative energy and exergy consumption are analyzed. Cumulative indices (such as cumulative energy consumption, cumulative exergy consumption, and thermo-ecological cost) quantify the total primary resources consumed throughout all steps of a production chain to obtain a specific final product.

The calculation of these cumulative indices relies on a system of mathematical balance equations solved via the balance method.

Defining Cumulative Indices

• Cumulative Energy Consumption (e*): The total energy consumption burdening all production processes, including transportation, leading to the considered final product.
• Cumulative Exergy Consumption (b*): The total exergy consumption burdening all production processes, including transportation, leading to the considered final product.
• Thermo-Ecological Cost (TEC): The total exergy consumed from non-renewable resources across all production and transportation processes for a final product, including additional exergy required to offset environmental impacts from waste emissions.