The thermal efficiency of a Brayton cycle can be increased by adding a regenerator as shown in the schematic below. Consider a Brayton cycle using air under the following conditions: T_A = 298 K, P_A = P_E = P_F = 0.1 MPa, P_B = 0.6 MPa, T_D = 973 K, T_F = 563 K. The efficiency of the turbine and compressor are to be 85%. Consider air as an ideal gas stream with C_P = 0.79·C_P,N2 + 0.21·C_P,O2, and assume the molar flows of B and E are equal. Determine the thermal efficiency, heat required, and net work output per mole of air, assuming

(a) The heat capacities are temperature-independent at the values at 298 K.

(b) The heat capacities are given by the polynomials in Appendix E.

Transcribed Image Text:

A Compressor F B Shaft Regenerator Heat (Fuel) Turbine D Combustion Chamber [1] E