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The performance of a cogeneration cycle with various working fluids is investigated and optimized with an economic approach. Exergy and exergoeconomic models are developed to investigate the thermodynamic performance of the cycle, and to assess the cost of products. In this study, the dynamic model would be registered to search the system behavior during a day. In this study, hydrogen production rate optimal design (HPROD) refrigeration power optimal design (RPOD) and cost optimal design (COD) are considered for analysis and optimization. According to recent parametric studies, boiler, turbine and condensation temperature and turbine inlet pressure affect the unit cost of products significantly. The results show the carbon dioxide and n-octane has a better operation to produce of hydrogen and refrigeration power among other working fluids, respectively. It is observed that, in carbon dioxide cycle, the SUCP is decreased by 8.5% when hydrogen production rate is decreased from 1.811 lit/s to 1.757 lit/s, therefore, in n-octane cycle, SUCP is decreased by 47.4% when refrigeration power is decreased from 9.599 KW to 6.622 KW. The evaluation of exergy destruction demonstrates in which the condenser has the highest exergy destruction, therefore, its rate in COD case is the lowest among the three other states. The results indicate, in carbon dioxide and n-octane cycles, the total exergy destruction and the investment cost rates in the RPOD case is higher than any other cases.

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In this paper, the performance of a new design cogeneration cycle with various working fluids is investigated. Exergoeconomic and exergoenvironmental approach are developed to study the thermodynamic performance of the cycle and to assess the total cost of products. The naval design is based on organic Rankine cycle by using the gas turbine prime mover for fulfilling of the main goals of gas comperessor station of Nar-Kangan zone (South of Iran). These goals as follows: production of electricity and refrigeration power (cooling requirement) and total cost of products. According to recent parametric studies, boiler, turbine and condensation temperature and turbine inlet pressure significantly affect the three goals. The results show that dichlorotrifluoroethane (R-123) and toluene have a better performance in producing electricity (1.612MW) and refrigeration power (6.282MW) among other working fluids, while, the carbon dioxide has a better operation to reduce of products cost (103.5$/MJ). So, when the condensation temperature increases the refrigeration power decreases and boiler inlet temperature increases, the refrigeration power decreases. The results reveal that the refrigeration power decreases as the turbine temperatures and pressure increase and condensation temperature decreases; however, there is an optimum turbine inlet pressure (12MPa) in the carbon dioxide cycle for a minimum cost of products. The combustion chamber and boiler have a maximum destruction exergy rate for irreversibility and temperature difference among of system components

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In recent years, the use of Gas Turbine-Modular Helium Reactor (GT-MHR) which operates in accordance with closed Brayton cycle with helium fluid as working fluid has attracted researchers’ attention because of its high efficiency, high reactor safety, being economical, and low maintenance costs. In the present study, a combined system, including GT-MHR cycle, Kalina cycle and Ammonia-water absorption cycle is investigated with respect to energy, exergy, and exergoeconomic. As the bottoming cycle, Kalina cycle and absorption cycle are used in order to avoid energy wasted by gas turbine cycle and to increase efficiency of energy conversion. The results of the simulated model show that, in the basic input mode, the overall work is 304462 kW, the overall exergy destruction is 289766kW and the overall exergy efficeincy of cogeneration cycle is 0.689kW. Also reactor, turbine and compressor in helium cycle are the component to which more attention should be paid with respect to exergoeconomic because the highest amount of cost rate is related to these components. At the end, parametric analysis is carried out in order to evaluate the effect of the changing pressure ratio of helium compressor, input temperature of helium compressor, input pressure and temperature of turbine and mass fraction of the base mode of the Kalina cycle on the output parameters.