Power Generation OBJECTIVE To examine vapor power plants in which the working fluid is vaporized and condensed.

Power Generation

OBJECTIVETo examine vapor power plants in which the workingfluid is vaporized and condensed

HEAT ENGINES

cyclic processes are used to convert thermal energy to useful work

problem is to design to maximize efficiency, , of conversion

condenser

boiler

Ws

Ws

Qc

QH

Power Generation

Carnot Cycle

Efficiency

Carnot cycle is the most efficient

Example

A steam plant operating under a Carnot cycle, uses steam at 100 C in the condenser and a pressure of 3 MPa at 600 C in the boiler. Assuming the pump and turbine operate reversibly, compute the efficiency of the cycle.

Ideal Rankine Cycle

standard for fossil fuel-burning power plants

isentropic pumping of liquid to boiler pressure constant pressure heating in boiler isentropic expansion in turbine constant T,P condensation

condenser

boiler

Wt

Wp

Qc

QH

Example

An ideal Rankine power station uses steam at 100 ºC in the condenser and a pressure of 3 MPa at 600 ºC in the boiler. Assuming the pump and turbine operate reversibly, compute the efficiency of the cycle.