Based on the following data, estimate the energy efficiency of the tested boiler.

- Duration of test: 1 hour

- Steam produced by boiler: 200,000 lbm

- Temperature and pressure of steam: 760F, 600 psia

- Temperature and pressure of feed water: 240F, 700 psia

- Fuel used (coal):15,385 lbm @ 80F, dry (HHV: 19,500 BTU/lbm of dry fuel)

- Temperature of combustion gases in the last heat recovery step: 450F

- Tdb and Twb of combustion air: 80F and 70F

- Barometric pressure at the test site: 29.92 in Hg

={Energyinputinfuel}{Enegyabsorbedbywater}=mfuelHVfuelmwater(hsteamhliq)