The Rational Efficiency of Power Plants and Their Components

The use of a rational efficiency for a power plant (the work output divided by the maximum possible reversible work output) is well established for conventional and combined plants. However, there are in the literature several proposals for “second-law” efficiencies of power plant components and no universally agreed practice. The paper discusses these various proposals and recommends particular definitions for the efficiency of components. These definitions are consistent with the universally agreed definition for overall plant rational efficiency. The approach is illustrated by a numerical example.