BeginnerTopic 33 of 105Thermodynamics & Fluids
Rankine cycle
Basic steam power plant cycle with boiler, turbine, condenser and pump.
In depth
Pump raises liquid pressure, boiler produces steam, turbine expands it for work, condenser rejects heat. η=(w_t-w_p)/q_in. Raising boiler pressure/temperature and lowering condenser pressure increases efficiency; moisture at turbine exit limits expansion.
Key points
- Pump work is small
- Condenser pressure 5–10 kPa
- Supercritical plants reach 45%
ExampleA coal plant at 16 MPa and 540 °C typically gets about 38%.
The Rankine cycle is the basis of most steam power plants, so its efficiency and design choices decide the cost and output of coal, nuclear and solar thermal plants.
What is Rankine cycle?
Basic steam power plant cycle with boiler, turbine, condenser and pump.
Why is it important to understand rankine cycle?
The Rankine cycle is the basis of most steam power plants, so its efficiency and design choices decide the cost and output of coal, nuclear and solar thermal plants.
What are the four components of the Rankine cycle?
A pump, a boiler, a turbine and a condenser, which together form a closed loop of water and steam.
Why does lowering the condenser pressure improve efficiency?
It lowers the heat rejection temperature, which increases the work the turbine can produce from the same steam.
How is Rankine cycle used in practice?
Typical applications include estimating the output of a coal plant from boiler and condenser conditions, choosing the condenser pressure for a steam turbine and comparing a supercritical plant with a subcritical plant of the same size.
What should I learn before Rankine cycle?
Study "Brayton cycle" first (topic 32 of 105 in Thermodynamics & Fluids). It covers the groundwork this topic builds on.
What are the key points of Rankine cycle?
Pump work is small. Condenser pressure 5–10 kPa. Supercritical plants reach 45%.
Can you give an example of Rankine cycle?
A coal plant at 16 MPa and 540 °C typically gets about 38%.
What comes after Rankine cycle?
The next topic is "Reheat and regeneration", which builds directly on this one.
How difficult is Rankine cycle?
It is classed as Beginner in Thermodynamics & Fluids (topic 33 of 105). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.