“…On the other hand, the previous works demonstrated that the hybrid systems can be constructed by integrating the large-scale power machinery and thermodynamics cycles such as gas turbine [6,7], Stirling heat engine [8], Brayton cycle [9], organic Rankine cycle [10], Braysson cycle [11] into the SOFC. Similarly, the hybrid systems can be established by coupling the SOFC with the small-scale energy conversion devices such as thermoelectric generator (TEG) [12], thermoelectric generator-cooler (TEGC) [13], vacuum thermionic energy converter (VTEC)-TEG [14], VTECs [15][16][17][18], and thermophotovoltaic (TPV) cells [19,20]. In the above-mentioned hybrid systems, the area matching between the subsystems was analyzed to predict the peak power density.…”