Exergoeconomic Design of the Geometry of a Vertical, Three Steps, Tubular Air Heater

Abstract

In this paper, the structural method of thermoeconomics is applied to find the optimal geometrical design to a vertical tubular air heater, whose original design is widely used on boilers installed on sugar mills. The objective function describes the running cost due to the temperature difference and pressure drop in function of the main geometrical parameters. The objective function is continuous in the interval of analysis and has a strong non linear behavior, then for solving it, the Optimization Toolbox from MATLAB 6.5 was used, through the function FMINCON, which uses an algorithm of medium scale, the Sequential Quadratic Programming (SQP) and the Cuasi Newton method. The new design reduces the running cost of equipment 1,97 US$/s compared to the one of RETO 45-28 system.