- #1
DavideGenoa
- 155
- 5
In the proof of Clausius inequality ##\oint\frac{\delta Q}{T}<0## for an irreversible cycle, I always find the fact that the thermal efficiency of an irreversible machine is **stricly less** than the thermal efficiency of a reversible machine, both operating between temperatures ##T_H## and ##T_C##.
Nevertheless my book and all the resources that I have found prove by reductio ad absurdum that, between the temperatures ##T_H## and ##T_C##, the thermal efficiency of an irreversible machine is (only) **less or equal** to the thermal efficiency of a reversible machine because, if it were strictly greater, the positive work done by an irreversible thermal machinee could be used to activate a reversible machine used as a chiller, and the resulting composed machine would produce a flow of heat from a cold source at the temperature ##T_C## to a hot one at the temperature ##T_H##, violating the second principle of thermodynamics.
How can it be proved that the thermal efficiency of an irreversible machine is strictly less than the thermal efficiency of a reversible machine operating between the same two temperatures ##T_C## and ##T_F##?
##\infty## thanks for any answer!
Nevertheless my book and all the resources that I have found prove by reductio ad absurdum that, between the temperatures ##T_H## and ##T_C##, the thermal efficiency of an irreversible machine is (only) **less or equal** to the thermal efficiency of a reversible machine because, if it were strictly greater, the positive work done by an irreversible thermal machinee could be used to activate a reversible machine used as a chiller, and the resulting composed machine would produce a flow of heat from a cold source at the temperature ##T_C## to a hot one at the temperature ##T_H##, violating the second principle of thermodynamics.
How can it be proved that the thermal efficiency of an irreversible machine is strictly less than the thermal efficiency of a reversible machine operating between the same two temperatures ##T_C## and ##T_F##?
##\infty## thanks for any answer!