Chart C

Average fuel cost Annual fuel savings

125,000 lb/hr

210 psig


8500 hr/yr 150 x 106 Btu/hr 129 x 106 Btu/hr $1.50/106 Btu

150 x 106 Btu/hr

Annual fuel savings corrected to actual operating conditions:

Savings $ = (curve value x [operating heat output)/

(design heat output)] x [actual annual operating hours)/(8,760 hr/yr)] = ($210,000/yr) x [(129 x 106 Btu/hr)/(150 x 106 Btu/hr)] x [(8,500 hr/yr)/(8,760 hr/yr)] = $175,200/yr

Notes: If the unit heat output or average fuel cost exceeds the limit of Figure 5.18, use half the particular value and double the savings obtained from Chart C. The annual fuel savings are based on 8,760 hr/yr. For an operating factor other that the curve basis, apply a correction factor to curve results. The application of the charts assumes operating at, or close to, optimum excess air values.

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