## 3 Simulation Scenarios and Results  
The parameters for the model inputs used in the simulation are given in Table 2 and the results obtained from the simulation using the input parameters given in Table 2 are presented in Table 3. The total net output of the system is 24,748 kW and the heat pump supplies 1385 kW of heat. The efficiency of the Brayton, Rankine, and overall cycles is 33%, 36%, and 62%, respectively. Furthermore, parametric studies are carried out to demonstrate the performance of the system through the variation of some design parameters for better performance analysis and the results are presented in this section. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Value** & **Unit** \\ \hline Pressure ratio of Brayton cycle & 5 & \\ Pressure ratio of heat pump & 2 & \\ Inlet pressure of Brayton cycle compressor & 100 & kPa \\ Outlet pressure of Rankine cycle pump & 10,000 & kPa \\ Efficiency of gas turbine, steam turbine, and pump & 85 & \% \\ Mass flow rate of Brayton cycle compressor inlet air & 40.92 & kg/s \\ Mass flow rate of Rankine cycle steam & 4.6 & kg/s \\ Mass flow rate of ammonia in the heat pump & 3 & kg/s \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Input variables used in the simulation. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Value** & **Unit** \\ \hline Brayton cycle compressor work & 7.41 & MW \\ Inlet combustion energy rate & 29.91 & MW \\ Brayton cycle net power output & 9.79 & MW \\ Rankine cycle pump work & 0.56 & MW \\ Rankine cycle net power output & 7.50 & MW \\ Heat pump compressor work & 0.15 & MW \\ Heat pump output & 1.39 & MW \\ Net power generated by the system & 24.75 & MW \\ Efficiency of Brayton cycle & 33 & \% \\ Efficiency of Rankine cycle & 36 & \% \\ COP of heat pump & 9.1 & \\ Overall energy efficiency of the system & 62 & \% \\ Overall exergy efficiency of the system & 78 & \% \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results obtained from the simulation. The impact of using different pressure ratios in the Brayton cycle on the compressor work, output power of the Brayton cycle, the combined power output of the Brayton and Rankine cycles, and overall power output is observed in Figure 2. An increase in the pressure ratio from 3 to 9 causes the compressor work to increase from 4.7 MW to 11.1 MW; this is because the compressor will have to perform more work to increase the exit pressure of the air after passing through it. The net power output from the Brayton cycle increases from 7.2 MW to 12.3 MW, while the power output from the combined Brayton and Rankine cycles increases from 14.6 MW to 19.6 MW. The net power output of the overall system is derived by subtracting the amount of work needed to drive the compressor of the heat pump compressor from the net power output of the combined power cycles. Figure 2 shows that increasing the Brayton cycle pressure ratio increases the overall net power output from 13.9 MW to 18.8 MW; this is because of the immense increase in the power output from the Brayton cycle which nearly doubles in value. Figure 3 explains the impact of the variation of the pressure ratio on the efficiencies of the Brayton cycle, the combined cycle, and the overall system. The effects observed in Figure 3 mirror those presented in Figure 2. For an increase in the pressure ratio from 3 to 9, the Brayton cycle efficiency increases from 24% to 42%. Moreover, the efficiency of the combined power cycles increases from 49% to 66%. It should be noted that combining a simple Rankine cycle to recover the exhaust heat from the Brayton cycle increases the combined cycle efficiency by about 25% compared to the Brayton cycle alone. The efficiency of the overall system also increases from 56% to 73%. Figure 4 examines the effect of varying the inlet pressure of the steam turbine on the steam turbine performance and the overall combined system performance.