| The concepts of "Thermoeconomic Functional Analysis" and "Thermoeconomic Isolation" initially introduced by Evans and Frangopoulos are further developed and their foundations completed. The first concept, based on Second Law analysis and typical Second Law costing techniques, is used to demonstrate, how a thermal system's thermoeconomic "basis" model is established and then optimized. Such a model simultaneously describes both the economic and thermodynamic behavior of the thermal system, and requires the complete functional breakdown of each of a system's physical components into either a conversion or a transmission function. This functional breakdown and the use of the Second Law reduce the overall complexity of the model by minimizing the number of required constraints and the number of unknowns in each function's thermoeconomic equation.; Once established, a "basis" model is optimized in order to determine the minimum cost of ownership and operation for the thermal system. If in the development of the "basis model", the concept of "Thermoeconomic Isolation" is combined with that of "Thermoeconomic Functional Analysis", then the model's optimization results not only in a minimum system cost but also in a stable economic environment around each function or component in the system. Such an environment allows each component to be optimized by itself without sacrificing the optimum design of the system as a whole.; As an illustration of all the above concepts, a thermoeconomic "basis" model for a Rankine reheat cycle without regeneration and one for a Rankine reheat cycle with regeneration are presented. They are optimized, demonstrating the ability on an economic and thermodynamic basis to optimally design or improve real-world thermal systems. The software employed uses a set of general numerical techniques which can create and minimize the thermoeconomic models not only of the Rankine cycles presented but of any number of other Rankine configurations.; Finally, a "detailed" thermoeconomic model of a three-zoned, high-pressure feedwater heater is presented in order to illustrate the techniques used to build "detailed" models for other system components. A discussion is given of how, once achieved, stable economic environments around individual components lead to isolated component optimizations which are consistent with overall system optimums. (Abstract shortened with permission of author.)... |
