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The productive structure and thermoeconomic theories of system optimization

Abstract:

The aim of this paper is to achieve a better understanding of the Thermoeconomic Theory of System Optimization and the Structural Theory of Cost (Valero et al., 1992, 1993), in order to unify and to take advantage of both theories. As the Thermoeconomic Functional Analysis (Frangopoulos, 1987, von Spakovsky, 1986), the methodology introduced in this paper, establishes that, each unit of the system has a purpose, i.e., a product to obtain, a function. For example, the function of a gas turbine is the work obtained when expanding the gases. This methodology is a general development of the Fuel-Product representation (Torres, 1991), based on the Structural Theory of Thermoeconomics. It gives a systematic and easy way to get a functional diagram from the physical scheme. This diagram represents the units, and the relations among themselves and the environment. Each unit uses a set of functions, or resources, from the environment or other units to obtain its function or product. Using as starting point the functional diagram, it is shown that the Structural Theory and the Thermoeconomic Functional Analysis are equivalent methods and get the same costs result values. Finally, the productive structure (causal diagram) is presented as the key structure to understand the formation of each product and then, to interrelate the whole structure. So, it could be used as a criterion to system disagregation, to obtain more accurate costs.