## 1 Introduction
Their results show that the efficiency can be achieved 43.11% and 42.03% using the fossil fuel and diesel fuel under similar conditions. In addition, the annual cost of using diesel fuel is about twice the cost of operating with natural gas fuel. [PERSON] et al. (2020) investigated and optimized a combined gas Brayton and Rankine cycle from an exergy, exergy-economic and environmental perspective. Parametric analysis is then performed to study the effect of compressor pressure ratio and Brayton gas turbine inlet temperature on the exergy efficiency and overall cost rate. The results showed that the highest amount of exergy destruction and cost rate occurred in the combustion chamber. The increase in Brayton turbine inlet temperature also results in a lower rate of exergy destruction cost of the combined cycle. [PERSON] et al. (2020) examined different configurations of the Brayton cycle including the simple Brayton cycle, the regenerative Brayton cycle, and the regenerative Brayton cycle with the specified mass fraction from an energy perspective. In the proposed new configuration, the fractional of the output fluid of the first turbine goes to the regenerator and the rest goes to the second turbine. The results showed that the use of the regenerative cycle over the simple cycle leads to an increase in energy efficiency (due to the reduction in fuel required by the combustion chamber inlet) and a decrease in the output work. In another study, [PERSON] (2020) examined and compared five different configurations including two Brayton and regenerative Brayton configurations and three Brayton gas cycle, simple reverse Brayton and regenerative reverse Brayton configurations from an energy perspective. In the new proposed configuration, the output gas mixture of the first turbine enters the second turbine and then goes to the regenerator. The results showed that at a certain range of pressure ratio, the use of regenerator improved the performance of the system. [PERSON] and [PERSON] (2020) studied the performance of the hybrid gas Brayton and air Brayton system with simultaneous actuator of combustion chamber and solar collector from a thermoeconomic perspective. The performance of the system is such that the upper exhaust gases from the turbine are used as an actuator for heat exchanger of lower cycle. Parametric analysis and optimization are performed to reduce the cost of electricity generation in the hybrid system. [PERSON] et al. (2020) analyzed the performance of the combined Brayton cycle and Rankine cycle power generation system from the exergyeconomic and environmental perspective. Biomass and solar energy are used as the upper Brayton cycle actuator in their system and the exhausted gas from the upper Brayton cycle is used as the Rankine cycle actuator. The results showed that by adding solar power to the system, the output power increased by 30% and carbon dioxide emissions decreased by 22%. Most research on the combined cycle systems have focused on the effect of different parameters on the Rankine cycle steam generator or the use of different configurations in the lower cycle to recover the gas turbine cycle dissipative energy, and so far, no comprehensive comparison has been made in the various configurations of the Brayton cycle of combined cycle power generation, which is the main motivation for the present study. Therefore, the results of this research represent over the possibility of recovering waste heat and determination of design parameters in the possible configurations of the combined cycle power plant with the purpose of power production. The main goals of the present paper are to manage the waste heat from the gas turbine to the Rankine cycle and to evaluate some possible configurations from the view of energy, exergy, exergoeconomics and environmental perspectives. In this research, the performance of different configurations of combined Brayton and Rankine cycle system is simulated and compared in terms of energy, exergy, exergy-economic and environmental factors.