Page 109 - Handbook of Energy Engineering Calculations
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vertically upward to the 1000-lb/in (abs) (6895.0-kPa) 1-in (3.4-kPa) curve.
At the left, read the theoretical heat rate as 8400 Btu/kWh (8862.5 kJ/kWh).
FIGURE 31 Theoretical heat rate for condensing turbines.
When the theoretical heat rate is known, the actual heat rate is found from:
actual heat rate HR, Btu/kWh = (theoretical heat rate, Btu/kWh)/(engine
efficiency). Or, actual HR = 8400/0.74 = 11,350 Btu/kWh (11,974.9
kJ/kWh).
3. Compute the full-load and steam rate
The energy converted to work, Btu/lb of steam = (available energy, Btu/lb of
steam) (engine efficiency) = (545) (0.74) = 403 Btu/lb of steam (937.4 kJ/kg).
For any prime mover driving a generator, the full-load output, Btu =
(generator kW rating) (3413 Btu/kWh) = (5000)(3413) = 17,060,000 Btu/h
(4999.8 kJ/s).
The steam flow = (full-load output, Btu/h)/(work output, Btu/lb) =
