Again neglecting the change in state of the feed water in passing through the feed pump, calculate the thermal efficiency of an ideal Rankine cycle in which the conditions of the fluid at inlet to and exit from the boiler are the same as those of the plant in P5.1. Thence confirm that the efficiency ratio of that plant is equal to the rational efficiency of the work-producing steam circuit calculated in P5.1.

[29.2\%; 83.3\%]

P5.1.

In a test of a steam power plant (Fig. P5.1), the measured rate of steam supply was \(7.1 \mathrm{~kg} / \mathrm{s}\) when the net rate of work output was \(5000 \mathrm{~kW}\). The condensate left the condenser as saturated liquid at \(38{ }^{\circ} \mathrm{C}\) and the superheated steam leaving the boiler was at \(10 \mathrm{bar}\) and \(300^{\circ} \mathrm{C}\).

Neglecting the change in state of the feed water in passing through the feed pump, and taking the environment temperature as being equal to the saturation temperature of the

condensate in the condenser, calculate the rational efficiency of the work-producing steam circuit (system A). Also calculate the thermal efficiency of the cyclic plant.
[83.3\%;24.3\%]

Transcribed Image Text:

FIGURE P5.1 SYSTEM B SYSTEM A W Turbine Boiler Turbine Condenser Lout W net Feedpump W Feedpump