Thermoeconomic optimization of a refrigeration plant

Abstract

In this paper, thermoeconomic theory is applied to the economic optimization of a conventional refrigeration plant, aimed at minimizing its overall operation and amortization cost. Thermal systems cannot always be optimized by means of mathematical or numerical techniques, because a complete model of the plant is not always available, and, in any case, mathematical difficulties are often great, even for not particularly complex systems, and the help of computerized algorithms is needed. In this paper, a simplified cost minimization methodology is applied, based on the so-called Theory of Exergetic Cost, here utilized to evaluate the economic costs of all the internal flows and products of the installation. As shown in the paper, once these costs have been calculated, a design configuration not far from the real global optimum can be obtained by means of a sequential, local optimization of the system, carried out unit by unit, that is, breaking down the global problem into a sequence of simpler problems. In the paper, the case of a very simple plant is considered to develop a numerical example, and, in spite of the approximations introduced to simplify the optimization procedure, the results obtained show acceptable accuracy when compared with those provided by a conventional and more complex optimization methodology.