Question

For a mercury-steam-sulphur oxide cycle, the heat rejected in the mercury cycle is given to the steam cycle and the heat rejected in the steam cycle is utilized in the sulphur oxide cycle are 0.4 and 0.3 and the overall efficiency is 0.72 then efficiency of the steam cycle is ________%.

• A. 33.33

Answer 1

The correct option is A 33.33
For 3 cycles coupled in series the overall efficiency of the combined cycle is give by
$\eta =1-(1-{\eta }_1)(1-{\eta }_2)(1-{\eta }_3)0.72=1-\left(\mathrm{1.0.4}\right)(1-0.3)(1-{\eta }_{steam})0.72=1-\left(0.42\right)(1-{\eta }_{steam})0.72=1-0.42+0.42{\eta }_{steam}\Rightarrow {\eta }_{steam}=0.3333=33.33$%