Optimizing Combined Cycle Performance: Analysis and Recommendations

[Tony_the_tiger]

Homework Statement

The figure below shows a combined cycle formed by a gas turbine and an organic Rankine bottoming cycle. Steady-state operating data are labeled on the figure. Owing to internal irreversibilities, the generator electricity output is 95% of the input shaft power. The regenerator preheats air entering the combustor. In the evaporator, hot exhaust gas from the regenerator vaporizes the bottoming cycle working fluid. For each of three working fluids - propane, Refrigerant 22, and Refrigerant 134a - specify workable ranges for p8 , turbine inlet pressure, and T8 , turbine inlet temperature; also determine turbine exit pressure p9 . For each working fluid, investigate the influence on net combined-cycle electricity production and on combined-cycle thermal efficiency of varying p8 , T8 , and compressor pressure ratio. Identify the bottoming cycle working fluid and operating conditions with greatest net combined-cycle electricity production. Repeat for greatest combined-cycle thermal efficiency. Apply engineering modeling compatible with that used in the course for Rankine cycles and air-standard analysis of gas turbines. Present your analyses, results, and recommendations in a clear summary report.

Homework Equations

The Attempt at a Solution

Can someone help me get this started or help me work through it. i am lost on how to do this.

 

[rock.freak667]

Firstly when presented with problems like these, I'd first try to draw everything on a T-S (temperature entropy diagram) or at least draw two separate diagrams for the two cycles. As it is now, you may be confused with the amount of information given based on that picture!