Talk:Engineering Thermodynamics/Second Law

Howdy There,

I have an issue with Clausius Statement in this module. I believe you will find that it should read: "..... without external effect ( e.g. external heat or work effect or both)."

A very real example of this distinction is the refrigerator in most recreation vehicles or some large tonnage chillers. Strictly a heat process between three ( or more ) temperatures. These are known generally as absorption refrigerators. No compressor or pumps.

Sincerely and cooperatively,

John Warner

I also have a sneaking suspicion that the Clausius / Kelvin-Planck equivalencies are backwards... I believe the first one actually violates Clausius first, which causes it to violate KP, and the second violates KP, causing it to violate Clausius. A minor quibble, I know.

Kyle

2nd law of thermodynamics..
2nd law of thermodynamics..Italic text

statement about kelvin-planck and clausius is just reverse ..

the true is :

Kelvin-Planck from Clausius

Suppose we have a heat engine which can convert heat into work without rejecting heat anywhere else. We can combine it with a heat pump so that the work produced by the engine is used by the pump. Now the combined system is a heat pump which uses no external work, violating the Kelvin-Planck statement of the second law.

Thus, we see that the Clausius and Kelvin-Planck statements are equivalent, and one necessarily implies the other.  Clausius from Kelvin-Planck

Now suppose we can construct a heat pump which transfers heat from a low temperature reservoir to a high temperature one without using external work. Then, we can couple it with a heat engine in such a way that the heat removed by the heat pump from the low temperature reservoir is the same as the heat rejected by the heat engine, so that the combined system is now a heat engine which converts heat to work without any external effect. This is thus in violation of the Clausius statement of the second law.

Reference from: Book Thermodynamics an Engineering Approach Seventh Edition in SI Units - Latest publish 2011 -