tailieunhanh - Advances in Gas Turbine Technology Part 4

Tham khảo tài liệu 'advances in gas turbine technology part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 80 Advances in Gas Turbine Technology then the required air for cooling fuel cell stack will decrease as shown in Figure 5. In addition due to the enhancement of cell stack activity the system exergy loss reduces and the total system output power increases as shown in Figure 6. When the operating temperature is above 920 c the voltage begins to decrease and system exergy losses increased. Therefore in the practical situation the system should operate in the proper temperature. Fig. 5. The effect of operating temperature on system performance Fig. 6. The effect of operating temperature on system exergy parameters Exergy Analysis of a Novel SOFC Hybrid System with Zero-CO2 Emission 81 The operating pressure The operating pressure is vital to the system performance. Improving the operating pressure of SOFC stack the SOFC voltage will increase because the H2 amount in SOFC stack and H2 partial pressure increase. Figure 7 shows that keeping the current density constant with the increase of the operating pressure the voltage increases. However the growth rate gets smaller. Fig. 7. The effect of operating pressure on SOFC Voltage Fig. 8. The effect of operating pressure on system exergy .