Question

1.

You will learn much about heat engine cycles in thermo

II (if you take it), but you already have the basic skills

needed to perform a rst law analysis of a simple vapor

power cycle. This cycle has four basic components: steam

turbine, condenser, liquid pump, and boiler, and four as-

sociated processes. A speci c case of this cycle has water,

in the form of a saturated vapor at 40 kPa, exiting from

the turbine and entering the condenser. The water leaves

the condenser as a saturated liquid at 40 kPa. The stream

now enters a pump, and exits at 5 MPa. For every kg of

water owing through the pump, the work input to the

pump is 6 kJ/kg. The stream next enters the boiler, and

exits at 450

◦

C and 5 MPa. This stream is routed to the

steam turbine inlet. Both the turbine and the pump can

be assumed adiabatic. The mass ow rate in the cycle is

20 kg/s. Determine

(a)

The net power output from the cycle (turbine power

produced minus pump power consumed).

(b)

The rate of heat transfer to the boiler.

(c)

The rate of heat transfer from the condenser.

(d)

The cycle thermal efficiency.

Answer 1