Can any ideal gas power cycle have a thermal efficiency greater than 55 percent when using thermal energy reservoirs at 627∘C at 17∘C? Explain. What is the maximum possible efficiency for such an engine?

Since the maximum thermal efficiency is higher than 55 percent, there can be a power cycle with these reservoir temperature with an efficiency higher than 55 percent.

Explanation:

The maximum thermal efficiency is determined from the given temperature

nth Carnot = 1 - TL/TH

Where TL = 17+273 = 290k

TH = 627*273 = 900K.

nth Carnot = 1 - 290/900 = 0.68

0.68*100 = 68 percent