Problems 411
13.16. Convert the data given in the table from kilowatt-hours
to Btu.
13.17. Assuming an average 35% efficiency for power plants
and a heating value of approximately 7.5 MJ/ kg, cal-
culate the amount of coal (in kg) required for generat-
ing electricity for each year shown in the table.
13.18. How many kilograms of coal could be saved if we were
to increase the average efficiency of power plants by 1%
to 36%?13.19. Assuming an average 35% efficiency for power plants
and a heating value of approximately 1000 Btu /ft
3(22,000 Btu / lbm), calculate the amount of natural gas
required in ft
3
and lbmfor generating electricity for
each year shown in the table.
13.20.How many ft
3
and pounds of natural gas could be
saved if we were to increase the average efficiency of
power plants by 1 to 36%?13.8. Investigate the typical power consumption range of the
following products:
a. home refrigerator
b. 25-inch television set
c. clothes washer
d. electric clothes dryer
e. vacuum cleaner
f. hair dryer
Discuss your findings in a brief report.
13.9. Investigate the typical power consumption range of the
following products:
a. personal computer with a 19-inch monitor
b. laser printer
c. cellular phone
d. palm calculator
Discuss your findings in a brief report.
13.10. Look up the furnace size and the size of the air-
conditioning unit in your own home or apartment.
Investigate the SEER and the AFUE of the units.
13.11. Investigate the size of a gas furnace used in a typical single-
family dwelling in upstate New York, and compare that
size to the furnaces used in Minnesota and in Kansas.13.12. An air-conditioning unit has a cooling capacity of
18,000 Btu /h. If the unit has a rated energy efficiency
ratio (EER) of 11, how much electrical energy is con-
sumed by the unit in 1 h? If a power company charges
14 cents per kWh usage, how much would it cost to
run the air-conditioning unit for a month (31 days),
assuming the unit runs 8 h a day? What is the co-
efficient of performance (COP) for the given air-
conditioning unit?
13.13.Visit a store that sells window-mount air-conditioning
units. Obtain information on their rated cooling
capacities and EER values. Contact your local power
company and determine the cost of electricity in your
area. Estimate how much it will cost to run the air-con-
ditioning unit during the summer. Write a brief report
to your instructor discussing your findings and
assumptions.
13.14.Calculate and plot the percentage of each fuel used in
generating electricity for each year shown in the
table.
13.15. Calculate and plot the percentage of increase in coal
consumption for the data shown in the table.Electricity Generation by Fuel, 1980 – 2030 (billion kilowatt-hours)—Data from U.S. Department of Energy
Year Coal Petroleum Natural Gas Nuclear Renewable /Other
1980 1161.562 245.9942 346.2399 251.1156 284.6883 actual values
1990 1594.011 126.6211 372.7652 576.8617 357.2381 actual values
2000 1966.265 111.221 601.0382 753.8929 356.4786 actual values
2005 2040.913 115.4264 751.8189 774.0726 375.8663 actual values
2010 2217.555 104.8182 773.8234 808.6948 475.7432 projected values
2020 2504.786 106.6799 1102.762 870.698 515.1523 projected values
2030 3380.674 114.6741 992.7706 870.5909 559.1335 projected valuesFor Problems 13.14 through 13.20 use the data from the accompanying table shown below.
Source:Data from U.S. Department fo Energy
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀