What are the energy conservation gains from the following:
a. Switching from a single 60-watt incandescent bulb that burns for 6 hours per day to a 13-watt CFL.
b. Using pure biodiesel instead of motor gasoline for an automobile that travels 60,000 miles per year with a fuel economy of 28 mpg.
c. Replacing a heat pump with a COP of 3.2 with a heat pump with a COP of 2.6, if the heating load is 43.3 million Btu per year.
d. Replacing an air conditioner with an EER of 11 with a unit that has an EER of 14, if the cooling load is 22 million Btu per year.
e. Upgrading a natural gas furnace from one with 88% efficiency to one with 92% efficiency, if the heating load is 55 million Btu per year.
What will be an ideal response?
a. (60w – 13w) x 6 hrs/day x 365 days/yr ÷ 1000 watts = 103 kWh/yr energy savings
b. 60,000 miles per year ÷ 28 mpg = 2,143 gallons per year energy savings
c. From Example 8.9:
Annual heating load in kWh = 12690.5 kWh/yr
Power required for COP 3.2 = 12690.5 kWh/yr ÷ 3.2 = 3,965.8 kWh/yr
Power required for COP 2.6 = 12690.5 kWh/yr ÷ 2.6 = 4,881 kWh/yr
We have replaced a more efficient system with a less efficient one, resulting in an increased energy use of 915.2 kWh per year.
So, a SEER 11 means that a system produces 11 Btu of cooling output for every watthour of electric input.
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____ oils were developed during World War II, when petroleum products were not widely available.
a. Natural b. Hybrid c. Multi-grade d. Synthetic
The accompanying figure is an example of a ½ ____________________ circuit.
Fill in the blank(s) with the appropriate word(s).
Cleaning the shop's floor is being discussed. Technician A says to flush the waste and dust into a floor drain. Technician B says a wet/dry vacuum cleaner with a HEPA filter is the preferred method. Who is correct?
A. A only B. B only C. Both A and B D. Neither A nor B
Repeat Problem 18.5 if
Problem 18.5
An iron-core inductor has the following characteristic:
a. Determine the energy, co-energy, and incremental inductance for ? = 1 V-s.
b. Given that the coil resistance is 1 ? and that i (t) = 0.625 + 0.01 sin 400t A
determine the voltage across the terminals on the inductor.