The steam requirements of a manufacturing facility are being met by a boiler whose rated heat input is 5.5 × 106 Btu/h. The combustion efficiency of the boiler is measured to be 0.7 by a handheld flue gas analyzer. After tuning up the boiler, the combustion efficiency rises to 0.8. The boiler operates 4200 h a year intermittently. Taking the unit cost of energy to be $13/106 Btu, determine the annual energy and cost savings as a result of tuning up the boiler.
The annual energy and cost savings.
Answer to Problem 56P
The annual energy and cost savings are
Explanation of Solution
Calculate the heat output of boiler.
Here, heat input of boiler is
Re-write Equation (I) if the current rate of heat input to the boiler is
Write the equation for the rate of useful heat output of the boiler.
Write the rate of heat input to the boiler after the tune up.
Write the rate of energy savings.
Calculate the energy savings.
Here, the operational hours is t.
Calculate the cost savings.
Conclusion:
Substitute
Substitute
Substitute
Substitute 4200 h/yr for t and
Substitute
Thus, the annual energy and cost savings are
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