THERMOECONOMIC OPTIMIZATION OF A COMBINED HEAT POWER CYCLE WITH STEAM SPLITTING

Abstract

The ever increase energy demand and decreasing energy resources has forced the engineeij and scientis? to rethink the design of energy conversion system. One possible way of addressing this issue is distributed generation, which substantially reduces distribution losses, however, smaller plants have lower efficiency and higher specific cost. This calls for an innovative system design technique like thennoeconomics that combines the thermodynamic analysis with economic constraints to obtain a system configuration that minimizes product cost. In this work, an attempt has been made to optimize a combined heat power system with the help of thermoeconomic analysis. First of all, the exergy analysis of the components is carried out to have an understanding of the performance of the components then a simplified cost minimization methodology is applied to evaluate the economic cost of all the internal flows and products of the installations. The conventional thermoeconomic optimization methods use interactive iterative procedure needing engineering judgment in each iterative step. A global optimization of the whole system is performed based on Evolutionary Programming of different plant units. The Evolutionary Programming optimization procedure, described herein, requires fewer computing resources and deals with simpler mathematical problems than conventional optimization methods. The analysis shows a reduction of 6.31% of the product cost of the plant with a reduction of 21.98% in capital investment. To improve the part load efficiency of the system steam recompression is considered. It is observed that under part load conditions the efficiency is not far away from the optimum operating conditions.