Question 1 A 2000 cubic cm Carnot engine using an ideal gas operates between two heat reservoirs. The source reservoir is at 800.0 K and the sink reservoir is at 300.0 K. The engine takes in 25 J of heat from the source reservoir per cycle.
a. Draw the T-s diagram (temperature versus entropy) for the cycle.
b. Find the work during each of the isothermal steps in the cycle.
c. Find the cycle efficiency.
d. What will be the efficiency of the engine if its volume is doubled? Question 2 Ten kilogram of Helium (assuming ideal gas) is used for a Carnot cycle. The cycle is 60% efficient and the heat transfer to the gas during the isothermal expansion is 40KJ and at the end of the isothermal expansion, the pressure is 5.6 bar and the volume is 0.3m3 .
Determine;
a. The maximum and minimum temperatures for the cycle, in K.
b. The pressure and volume at the beginning of the isothermal expansion in bar and m3 respectively.
c. The work and heat transfer for each of the four processes in KJ.
d. Sketch the cycle on p-v coordinates. Question 3 Saturated vapor enters the turbine of an ideal Rankine cycle at 1000 psia and is condensed after adiabatically expanded to the atmospheric pressure.
a. What is the approximate quality of the steam exiting the turbine?
b. What is the Rankine cycle efficiency?
c. Compare the Rankine cycle efficiency with the Carnot efficiency at the same source/sink temperatures.