Thermoeconomic Analysis And Performance Evaluation Of Gas-steam Combined Cycle Power Plants Based On H&S Model

Compared with common coal-fired power stations, gas-steam CCPPs have the advantages of utilizing energy clearly, efficiently and gradually, which makes for the development of the power industry. The research has become a hot area of research. Thermoeconomics combines the thermodynamics with economic principles, states how the cost of each components form and provides information that is useful to the design and operation of a cost-effective system. In this paper, the typical 9FA single shaft gas-steam combined cycle generating unit is analyzed and evaluated based on the new structure theory of thermoeconomics.First, the basic important concepts in the field of thermoeconomics are summarized. The components are divided into three kinds in the aspect of producing function. The concept of energy integration level is summarized, and several cases based on exergy are explained. In addition, the approach to calculation and apportionment of non-energy cost is analyzed.Then, the source and significance of negentropy in the field of thermoeconomics is tracked and the quantitative relation between the amount of negentropy produced and that consumed is presented, which considers the Brayton cycle and the Rankine cycle. The comparison is made between the traditional distribution method of negentropy and the new proposed one by calculating the consumption of negentropy, proportion of negentropy consumption, specific consumption of negentropy and negentropy cost.Furthermore, a new improved thermoeconomic analysis and evaluation method based on the structure theory of thermoeconomics and H&S theory is proposed. The concepts of production efficiency and the concept of dissipative cost are put forward. The H&S model can solve the problem of definition of dissipative components’ fuel and product in thermodynamics viewpoint, also the productive components are evaluated fairly. The reasonability and the accuracy are verified from multiple perspectives. The effect of non-energy cost and the changes of natural gas’s price on thermoeconomic cost of components are analyzed.At last, the thermoeconomic cost is decomposed to four parts, which are simply enthalpy cost, dissipation cost, negentropy cost and non-energy cost. Based on above analysis, the new evaluation index, namely non-energy factor is proposed, which can be used to give a pretty reasonable and obtain a good result of directions for optimization.