Endoreversible Carnot engine

The T-s diagram and schematic diagram of the Curzon and Ahlborn (endoreversible Carnot) cycle are shown in Figs. 7.5 and 7.6, respectively (Cuzon, F.L. and Ahlborn, B., Efficiency of a Carnot engine at maximum... 

Equation (7.21) is the optimal performance characteristics of the endoreversible Carnot heat engine. It indicates that P = 0 when y = 0 and iy = iyc = 1 — Pl/Ph- Taking the derivative of P with respect to y and setting it equal to zero (dP/diy = 0) gives... 

The power versus efficiency characteristics of the endoreversible Carnot heat engine is a parabolic curve. The endoreversible heat engine is a simple model, which considers the external heat-transfer irreversibility between the heat engine and its surrounding heat reservoirs only. 

Finally, we want to point out that the concept of the endoreversible engine is a simplification that leads to a quick and clear insight into the role and thermodynamic cost of transfer processes in reducing the Carnot efficiency into smaller and more realistic values. But for finding the real optimum conditions, the concept of endoreversibility has to be sacrificed. This will complicate the matter to some extent but will allow for including all contributions to the lost work ... 

Fig. 14.6. Optima for an endoreversible, finite-time Carnot-type engine with finite...

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