ME320 solution9

# ME320 solution9 - ME320 Thermodynamics Homework set#9 Due...

This preview shows pages 1–2. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ME320 Thermodynamics Homework set #9 Due: Wednesday 11/19/03 at the start of class 1. Someone claims to have developed a new reversible heat-engine cycle that operates between two temperature reservoirs has a higher oper- ating efficiency than a Carnot cycle operating between the same two reservoirs. How do you evaluate this claim? Solution: The claim violates the second Carnot principle and thus is false. 2. An inventor claims to have developed a heat engine that receives 750 kJ of heat from a source of 400 K and produces 250 kJ of net work while rejecting waste heat to a sink at 300 K. Is this a rasonable claim? Why? Solution: The highest thermal efficiency possible for a heat engine operating be- tween two specified temperature limits is the Carnot efficiency, which for T L = 300 K and T H = 400 K yields η th,max = 1- T L T H = 1- 300 K 400 K = 1 4 . However, using directly the given values W net = 250 kJ and Q H = 750 kJ for the net work and waste heat yields a thermal efficiency η...
View Full Document

{[ snackBarMessage ]}

### Page1 / 2

ME320 solution9 - ME320 Thermodynamics Homework set#9 Due...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online