EXERGETIC EVALUATION OF REGENERATOR AND REHEATER BASED COMBINED CYCLE GAS POWER PLANT

Abstract

Exergetic evaluation of combined vapour power cycle (CVPC) with regeneration and reheating is done in this study. Energy analysis gives quantitative aspect of the energy while exergy analysis is more qualitative. Due to lack of quality in the thermodynamic process there is wastage of energy which can be also denoted by another term i.e. exergy destruction and it affects the system’s efficiency. A separate analysis has to be done for every major component we have and the whole information about losses occurring in the system along with their locations will be the outcome of this analysis. This outcome is very useful in analysing these mechanical components as it will define qualitative and quantitative aspect of the major losses occurring inside the system. This way of optimisation improves system performance by decreasing exergy destruction and exergy losses along with the increase in exergetic efficiency. Amount of exergy losses may vary in different components hence our primary objective is to perform energy analysis of these components and also pick those sites which are having major losses whether in the form of energy or exergy. This can also be done at different parameters, by varying load to get more accurate figures. Exergy flow rate at inlet and outlet of different components of a system is carried out like regenerators pumps and turbines. After performing all the calculations, we found that combustion chamber is the largest source of exergy destruction. Our calculations are based on the difference of exergy inflow and outflow. We have N number of parameters which can affect system performance i.e. pressure ratio, AFR, temp. at inlet to compressor, ambient temperature, etc. but we will see the effect of AFR and inlet temp. on the exergy destruction rate of various components. With the use of EES a program code is made to perform basic calculations required in this area of exergetic evaluation.