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.

Question

Sawyer

Physics

3 October, 21:48

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.

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Seth Sherman · 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