Page 115 - Handbook of Energy Engineering Calculations

gross heat rate is computed by using the generator-terminal output; the net
heat rate is computed after the feedwater-pump energy input is deducted from
the generator output.

FIGURE 36 Full-load heat rates for steam turbines with six
feedwater heaters, 1000°F/1000°F (538°C/538°C) steam, 1.5-in (38.1-

mm) Hg (abs) exhaust pressure.

2. Determine the cross-compound turbine heat rate
“Enter Fig. 37 at 350 mW at the bottom, and project vertically upward to 1.5-
inHg (5.1-kPa) exhaust pressure midway between the 1- and 2-inHg (3.4- and
6.8-kPa) curves. At the left, read the net heat rate as 7880 Btu/kWh (8313.8
kJ/kWh). Thus, the reheat-regenerative unit has a lower net heat rate. Even at

full rated load of the cross-compound turbine, its heat rate is higher than the