Numerical - Max efficiency of a heat engine at a given source and sink temperature
A cyclic heat engine operates between a source temperature of 927 0C and a sink temperature of 27 0C. What will be the maximum efficiency of the heat engine?
Options
a. 100 %
b. 80 %
c. 75 %
d. 70 %
Correct Answer: c. 75 %
Explanation
Heat engine is operated between the temperatures
T1 = 927 0C = 927 + 273 = 1200 K and
T2 = 27 0C = 27 + 273 = 300 K
The maximum efficiency of a heat engine is given by,
ηmax = 1 – (T2/T1)
ηmax = 1 – (300/1200)
ηmax = 0.75
