An ideal combination of cyclic plants

Consider a combined power plant made up of two cyclic plants (H, L) in series (Fig. 7.1). In this ideal plant, heat that is rejected from the higher (topping) plant, of thermal efficiency tjh, is used to supply the lower (bottoming) plant, of thermal efficiency tjl, with no intermediate heat loss and supplementary heating. 

The thermal efficiency of the combined plant is greater than that of the upper cycle alone, by an amount 7Jl(1 — tjh). 

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