Example: Carnot Efficiency
The inventor claims to contain an engine which receives 100 Btu of heat and generates 25 Btu of useful work whenever operating among a source at 140°F and a receiver at 0°F. Is the claim is valid?
Solution:
TH = 140oF + 460 = 600°R
TC =0oF + 460 = 460°R
η = (600-460)/600 x 100 = 23.3%
Claimed efficiency = 25/100 = 25%
Hence, the claim is not valid.