Answer to Question #250430 in Physical Chemistry for mickey

Question

Compare the thermodynamic efficiencies to be expected:
(a) When an engine is allowed to operate between 1000 K and 300 K.
(b) When an engine is allowed to operate between 1000 K and 600 K and then waste heat
passed on to another engine which operates between 600 K and 300 K.

Answer 1

The efficiency of a reversible engine operating between 1000k and 300k is 70%

The above efficiency is called Carnot cycle efficiency, it is the maximum possible theoretical efficiency and can’t be obtained practically because of heat loss to the surroundings.

Here TL=300K, TH=1000K

So Carnot efficiency is (1-(TL/TH))=0.7