Workshop: Chapters 8,9 and 6
CHEN2001 | CHEN5025
QUESTION 1 (Q8.3 in your textbook)
A steam power plant operates on a Rankine cycle with a turbine efficiency η(turbine) = 0.80 and a pump efficiency
η(pump) = 0.75. Draw a TS diagram of the cycle and for the following operating conditions, determine:
(a) the steam rate,
(b) the heat-transfer rates in the boiler and condenser, and
(c) the thermal efficiency of the plant.
Boiler pressure P1 = P2 = 10,000 kPa;
Steam entering turbine: T2 = 600°C;
Condenser pressure P3 = P4 = 10 kPa;
Power rating = 80,000 kW.
Relevant H, S and V data are found in your steam tables as shown below:
Interpolated values at
10 kPa:
T = 45.83°C
Hl = 191.832 kJ kg-1
Hv = 2584.8 kJ kg-1
Vl = 1.010 cm3 g-1
Sl = 0.6493 kJ kg-1 K-1
Sv = 8.1511 kJ kg-1 K-1
QUESTION 2 (Q9.7 in your textbook)
A Carnot engine is coupled to a Carnot refrigerator so that all of the work produced by the engine is used by the
refrigerator in extraction of heat from a heat reservoir at 0°C at the rate of 35 kJ⋅s−1. The source of energy for the
Carnot engine is a heat reservoir at 250°C.
(a) If both devices discard heat to the surroundings at 25°C, how much heat does the engine absorb from its
heat-source reservoir?
(b) If the actual coefficient of performance of the refrigerator is ω = 0.6 ωCarnot and if the thermal efficiency
of the engine is η = 0.6 ηCarnot, how much heat does the engine absorb from its heat-source reservoir?
QUESTION 3 (based on chapter 6.1 in your textbook)
𝜕𝜕𝜕𝜕
𝜕𝜕𝜕𝜕
𝜕𝜕𝜕𝜕
𝜕𝜕𝜕𝜕
� = 𝐶𝐶𝑣𝑣 + [𝑇𝑇 � � − 𝑃𝑃] � � . What does the partial derivative � � become for an Ideal
𝜕𝜕𝜕𝜕 𝑃𝑃
𝜕𝜕𝜕𝜕 𝑉𝑉
𝜕𝜕𝜕𝜕 𝑃𝑃
𝜕𝜕𝜕𝜕 𝑃𝑃
Show that �
Gas gas, or for a gas for a different P-V-T relationship?
Western Australian School of Mines, Minerals and Chemical Engineering