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Reheat Rankine Cycle Efficiency Calculation
Published on July 2, 2026
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Calculate the thermal efficiency, work ratio, and specific steam consumption for a reheat Rankine cycle using steam turbine efficiencies and given operating conditions.
Question
Answer
To solve this problem, we will analyze the reheat Rankine cycle step-by-step. Since steam tables are not provided in the prompt, I will use standard thermodynamic properties for water/steam.
1. State Point Analysis
State 1: High-Pressure (HP) Turbine Inlet
-
, - From superheated steam tables:
,
State 2: HP Turbine Outlet
- The steam leaves as saturated vapour. From saturated steam tables at
(where for an ideal process): - Since it leaves as saturated vapour,
at . - To find
, we look for the pressure where . - At
, . Let’s assume . -
. - Isentropic enthalpy
: For at , (approx saturated). - Actual work
. - Check efficiency:
. This helps refine if needed, but we follow the “saturated vapour” constraint.
State 6: Low-Pressure (LP) Turbine Inlet (after reheat)
-
, - From superheated tables:
,
State 7: LP Turbine Outlet
-
- Isentropic state
: . - At
: . -
-
- Actual enthalpy
: -
State 3: Condenser Outlet / Pump Inlet
- Saturated liquid at
. -
,
State 4: Pump Outlet
- Isentropic pump work:
- Actual pump work:
-
2. Calculations
Total Work Output (
Total Heat Input (
Cycle Efficiency (
Work Ratio:
Specific Steam Consumption (SSC):
Final Answers:
- Cycle Efficiency:
- Work Ratio:
- Specific Steam Consumption: