- #1
sangsang
- 1
- 0
I do not really understand the reason why Carnot ideal engine needs 4 cycles: isothermal expansion, adiabatic expansion, isothermal compression, adiabatic compression. Why cannot use only 2 cycles said isobaric expansion and isobaric compression, i.e. use a heat reservoir to expand the air inside the engine, then use a cold reservoir to compress the air?
I even checked the original paper of Carnot and it explains as below, but I am not very understand for the following 2 processes,
1) use hear reservoir to increase the temperature of air to expand
2) use compression to increase the temperature first, then use an isothermal expansion to expand
Why 1 is less efficiency then 2 as Carnot said?
[Since every re‐establishment of equilibrium in the caloric may be the cause of the
production of motive power, every re‐establishment of equilibrium which shall be
accomplished without production of this power should be considered as an actual loss.
Now, very little reflection would show that all change of temperature which is not due to a
change of volume of the bodies can be only a useless re‐establishment of equilibrium in the caloric.]
I even checked the original paper of Carnot and it explains as below, but I am not very understand for the following 2 processes,
1) use hear reservoir to increase the temperature of air to expand
2) use compression to increase the temperature first, then use an isothermal expansion to expand
Why 1 is less efficiency then 2 as Carnot said?
[Since every re‐establishment of equilibrium in the caloric may be the cause of the
production of motive power, every re‐establishment of equilibrium which shall be
accomplished without production of this power should be considered as an actual loss.
Now, very little reflection would show that all change of temperature which is not due to a
change of volume of the bodies can be only a useless re‐establishment of equilibrium in the caloric.]