Processes Camot cycle

Figure 4.3 Reversible Camot cycle, showing steps (1) reversible isothermal expansion at th (2) reversible adiabatic expansion and cooling from th to tc (3) reversible isothermal compression at tc (4) reversible adiabatic compression and heating back to the original starting point. The total area of the Camot cycle, P dV, is the net useful work w performed in the cyclic process (see text).

Then, necessarily, the mirror, the reverse Camot Cycle O (the transfer channel K ) is to be constructed with that step-aside (excluding that stationarity) from the observed 0 = K. Now we mean that the step-aside of the observing process O from the observed process O is realized by the difference Tw-T w >0. Now, within this thermodynamic point of view, it is valid that... 

Then we need a mirror, the reverse Camot Cycle O =T (or the relevant transfer channel K ) would be constructed in such a way that the mentioned step-aside from the observed transfer channel K was respected. [It is the step-aside of the observing process (O, T) from the observed process (O, 7) also we can consider a computing process k and its description -the program rj, and its observation, see later]. 

The Camot cycle is formulated directly from the second law of thermodynamics. It is a perfectly reversible, adiabatic cycle consisting of two constant entropy processes and two constant temperature processes. It defines the ultimate efficiency for any process operating between two temperatures. The coefficient of performance (COP) of the reverse Camot cycle (refrigerator) is expressed as... 

Hence, at least for fast irreversible reactions, by (6.2.113) the loss of exergy is enormous whatever be the arrangement of the process. Classical thermodynamics knows still another hypothetical device in addition to the reversibly-working Camot cycles, viz. the reversible galvanic (electrochemical) cell. In this device, with constant volume the electric work (say) equals the affinity of the reaction, per unit integral reaction rate. Thus considering the cell working at temperature Tq with pure species, we have... 

Fig. D.2 Ccimot cycle (a) process of Camot cycle (b) state diagram of Camot cycle...

A reversible Camot cycle O mnning in (producing noise heat AQoi = 0) can be considered to be a thermodynamic, average-value realization or, as such, as a model of an information transfer process running in a channel 1C without noise. For the average noise information (entropy) H Y X) defined in (8) it is valid that H(Y X) = 0. 

Figure 3.2 The Carnot cycle. The upper part shows the four steps of the Camot cycle, during which the engine absorbs heat from the hot reservoir, produces work and returns heat to the cold reservoir. The lower part shows the representation of this process in a p-V diagram used by Clapeyron in his exposition of Carnot s work...

The energy transfers involved in one cycle of a Camot engine are shown sehematieally in Fig. 4.5(a). When the cycle is reversed, as shown in Fig. 4.5(b), the deviee is eaUed a Carnot heat pump. In each cycle of a Carnot heat pump, gh is negative and qc is positive. Since each step of a Carnot engine or Carnot heat pump is a reversible process, neither device is an impossible device. 

The significance of the reversibility of the above processes is that at the end of the cycle the system is brought back to its starting point with no losses incurred due to friction or other causes. Thus, as the system temperature is restored to its starting point T, its pressure is also restored to its starting level of P. If the processes are not reversible, additional work woirld have to be done on the system to bring the pressure back to P,. The net work would be less than G2 Gn and the efficiency would be lower than the Camot efficiency. 

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