Energetic and Exergetic Performance Analyses of Solar Dish Based CO2 Combined Cycle

Abstract

This paper presents a conceptual configuration of a solar dish based combined cycle power plant with a topping gas turbine block and a bottoming steam turbine cycle coupled through a heat recovery steam generator (HRSG). Carbon dioxide has been considered as the working fluid for the topping cycle and it has been considered in gaseous state all through the cycle. Two-stage compression has been proposed for the carbon dioxide cycle. The conventional GT combustion chamber is replaced by a high-temperature directly irradiated annular pressurized receiver (DIAPR) consisting of cavity and tubular sections. Detail thermodynamic study has been performed for varying second stage pressure ratioand for varying gas turbine inlet temperature for the combined cycle keeping first stage pressure ratio fixed at 3.The gas turbine inlet temperature has been varied from 625 O C to 900 O C. The study reveals that work output of the combined cycle is maximum when the pressure ratio of the second stage compression is 2. Parametric exergetic analysis has also been performed for the components like dish, solar receiver and stack. The exergy analysis shows that the solar receiver contributes to maximum exergy destruction.