Question

An engine manufacturer makes the claim that the engine they have developed will, on each cycle, take 100 j of heat out of boiling water at 100°c, do mechanical work of 80 j, and exhaust 20 j of heat at 10°c. what, if anything, is wrong with this claim? the efficiency of this engine is greater than the ideal carnot cycle efficiency.

Answer 1

hot reservoir temp 100

cold res temp= 10

eff = (1- cold/hot)x100%

by temperatures eff = (1-10/100)x100 ... by heat transfers eff = (1-20/100)x100

the claims seem to disagree

eff = 90% .... very high. 80%

a carnot may be about 70% If it is reversible and is between two reservoirs