Power Plant
Power Plant tests thermodynamic cycles, boiler and condenser performance, turbine expansion, heat rate, and plant auxiliaries.
Core rules and concepts
- Rankine cycle: pump work is approximately v delta P; boiler heat input is h_1-h_4; turbine work is h_1-h_2; efficiency is (W_t-W_p)/Q_in.
- Reheat raises the average heat-addition temperature; regeneration reduces irreversibility by heating feedwater with extracted steam.
- Condenser vacuum improves cycle efficiency but is limited by cooling-water temperature and air in-leakage.
- Boiler efficiency is useful heat divided by chemical energy input; account for stack loss, unburned carbon, radiation, and blowdown.
- Heat rate is 3600/eta in kJ/kWh with consistent units; lower heat rate is better.
Worked example
Steam enters a turbine at h_1=3000 kJ/kg and leaves at h_2=2000 kJ/kg. Condensate enthalpy is h_4=210 kJ/kg and pump work is 10 kJ/kg. Turbine work is 1000 kJ/kg; net work is 990 kJ/kg; heat input is 3000-210=2790 kJ/kg. Cycle efficiency is 990/2790=0.355, or 35.5%. The condenser rejects h_2-h_3, not the full turbine work.
Traps
Using internal energy instead of enthalpy for steady-flow devices, forgetting pump work, treating condenser pressure as atmospheric, and mixing kJ/kg with kJ/kWh are frequent errors. Reheat is not automatically beneficial at every pressure.