Exergy and Exergoeconomic Analysis and Optimization of the Cogeneration Cycle Under Solar Radiation Dynamic Model Using Genetic Algorithm

Abstract

The performance of a CO2 transcritical hydrogen production/refrigeration cogeneration cycle is investigated and optimized with an economic approach. Exergy and exergoeconomic models are developed in order to investigate the thermodynamic performance of the cycle and assess the unit cost of the cycle products. In this study, hydrogen exergy efficiency optimal design (HEEOD), refrigeration power optimal design (RPOD), and cost optimal design (COD) are considered for analysis and optimization. According to recent parametric studies, boiler and turbine inlet temperature, turbine inlet pressure, condensation, and LNG inlet temperature significantly affect the unit cost of products. The results show that the sum of the unit cost of products (SUCP) is obtained through exergoeconomic optimization; in the three cases of HEEOD, RPOD, and COD, it is, respectively, 24.2%, 24%, and 32.7% lower than the base case. It was observed that the SUCP is decreased by 8.5% when hydrogen production rate is decreased from 1.811 lit/s in HEEOD case to 1.756 lit/s in COD case. The evaluation of exergy destruction, for each component of system in three cases of optimization, demonstrates in which the condenser has the highest exergy destruction due to high-temperature difference; therefore, the exergy destruction of condenser in COD case is the lowest among the three other states. The results indicate the total exergy destruction and the investment cost rates in the RPOD case are higher than any other cases.