Guide to Energy Management, 8th Edition
By Capehart, Chapter 1-13
SOLUTION MANUAL
, Table of Contents
Chapter 1: Introduction to Energy Management .................................. 1
Chapter 2: The Energy Audit Process: An Overview ........................ 15
Chapter 3: Understanding Energy Bill .................................................. 21
Chapter 4: Economic Analysis and Life Cycle Costing ..................... 37
Chapter 5: Lighting ................................................................................... 53
Chapter 6: Heating, Ventilating, and Air Conditioning .................... 69
Chapter 7: Combustion Processes and the
Use of Industrial Wastes ...................................................... 83
Chapter 8: Steam Generation and Distribution................................. 103
Chapter 9: Control Systems and Computers ......................................111
Chapter 10: Maintenance ......................................................................... 119
Chapter 11: Insulation .............................................................................. 127
Chapter 12: Process Energy Management ............................................ 141
Chapter 13: Renewable Energy Sources and Water ........................... 149
Management Supplemental ......................................................................... 158
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v
, Chapter 1
Introduction to Energy Management
Problem: For your university or organization, list some energy man-
agement projects that might be good “first ones,” or early
selections.
Solution: Early projects should have a rapid payback, a high prob-
ability of success, and few negative consequences (increas-
ing/decreasing the air-conditioning/heat, or reducing
lighting levels).
Examples:
Switching to a more efficient light source (especially
in conditioned areas where one not only saves with
the reduced power consumption of the lamps but also
from reduced refrigeration or air-conditioning load).
Repairing steam leaks. Small steam leaks become large
leaks over time.
Insulating hot fluid pipes and tanks.
Install high efficiency motors.
Process Engineering Channel
And many more
@ProcessEng
1
, 2 Solutions Manual for Guide to Energy Management
Problem: Again for your university or organization, assume you are
starting a program and are defining goals. What are some
potential first-year goals?
Solution: Goals should be tough but achievable, measurable, and
specific.
Examples:
Total energy per unit of production will drop by 10
percent for the first and an additional 5 percent the
second.
Within 2 years all energy consumers of 5 million British
thermal units per hour (Btuh) or larger will be sepa-
rately metered for monitoring purposes.
Each plant in the division will have an active energy
management program by the end of the first year.
All plants will have contingency plans for gas cur-
tailments of varying duration by the end of the first
year.
All boilers of 50,000 lbm/hour or larger will be exam-
ined for waste heat recovery potential the first year.
Process Engineering Channel
@ProcessEng
, Introduction to Energy Management 3
Problem: Perform the following energy conversions and calcula-
tions:
a) A spherical balloon with a diameter of ten feet is filled
with natural gas. How much energy is contained in
that quantity of natural gas?
b) How many Btu are in 200 therms of natural gas? How
many Btu in 500 gallons of 92 fuel oil?
c) An oil tanker is carrying 20,000 barrels of #2 fuel oil.
If each gallon of fuel oil will generate 550 kWh of
electric energy in a power plant, how many kWh can
be generated from the oil in the tanker?
d) How much coal is required at a power plant with a
heat rate of 10,000 Btu/kWh to run a 6 kW electric
resistance heater constantly for 1 week (16 8 hours)?
e) A large city has a population which is served by a
single electric utility which burns coal to generate
electrical energy. If there are 500,000 utility customers
using an average of 12,000 kWh per year, how many
tons of coal must be burned in the power plants if the
heat rate is 10,500 Btu/kWh?
f) Consider an electric heater with a 4,500 watt heating
element. Assuming that the water heater is 98% effi-
cient, how long will it take to heat 50 gallons of water
from 70 degree F to 140 degree F?
Process Engineering Channel
@ProcessEng
, 4 Solutions Manual for Guide to Energy Management
Solution:
a) V = 4/3 (PI) P
= 4/3 × 3.14 × 53
523.33 ft3
E = V × 1,000 Btu/cubic foot of natural gas
= 523.33 ft3 X 1,000 Btu/ft3
= 523,333 Btu
b) E = 200 therms × 100, 000 Btu/therm of natural gas
= 20,000,000 Btu
E = 500 gallons × 140,000 Btu/gallon of #2 fuel oil
70,000,000 Btu
c) E = 20,000 barrels × 42 gal./barrel × 550 kWh/gal.
4.6E+08 kWh
d) V = 10,000 Btu/kWh × 6 kW × 168 h/25,000,000
Btu/ton coal
= 0.40 tons of coal
e) V = 500,000 cus. × 12,000 kWh/cus. × 10,500
Btu/kWh × I ton/25,000,000 Btu
= 2,520,000 tons of coal
f) E = 50 gal. × 8.34 lbm/gal. × (140F - 70F) ×
1 Btu/F/lbm
= 29,190 Btu
= 29,190 Btu/3,412 Btu/kWh
= 8.56 kWh
Process Engineering Channel
= 8.56 kWh/4.5 kW/0.98
= 1.94 h
@ProcessEng
, Introduction to Energy Management 5
Problem: If you were a member of the upper level management in
charge of implementing an energy management program
at your university or organization, what actions would you
take to reward participating individuals and to reinforce
commitment to energy management?
Solution: The following actions should be taken to reward individu-
als and reinforce commitment to energy management:
Develop goals and a way of tracking their progress.
Develop an energy accounting system with a perfor-
mance measure such as Btu/sq. ft or Btu/unit.
Assign energy costs to a cost center, profit center, an
investment center or some other department that has
an individual responsibility for cost or profit.
Reward (with a monetary bonus) all employees who
control cost or profit relative to the level of cost or
profit. At the risk of being repetitive, note that the level
of cost or profit should include energy costs.
Process Engineering Channel
@ProcessEng
, 6 Solutions Manual for Guide to Energy Management
Problem: A person takes a shower for ten minutes. The water flow
rate is three gallons per minute, the temperature of the
shower water is 110 degrees E Assuming that cold water
is at 65 degrees F, and that hot water from a 70% efficient
gas water heater is at 140 degrees F, how many cubic feet
of natural gas does it take to provide the hot water for the
shower?
Solution: E = 10 min × 3 gal./min × 8.34 lbm/gal ×
(110 F - 65 F) × 1 Btu/lbm/F
= 11,259 Btu
V = 11,259 Btu × 1 cubic foot/1,000 Btu/0.70
= 16.08 cubic feet of natural gas
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, Introduction to Energy Management 7
Problem: An office building uses 1 Million kWh of electric energy
and 3,000 gallons of #2 fuel oil per year. The building has
45,000 square feet of conditioned space. Determine the
Energy Use Index (EUI) and compare it to the average EUI
of an office building.
Solution: E(elect.) = 1,000,000 kWh/yr. × 3,412 Btu/kWh
= 3,412,000,000 Btu/yr.
E(#2 fuel) = 3,000 gal./yr. × 140,000 Btu/gal.
= 420,000,000 Btu/yr.
E = 3,832,000,000 Btu/yr.
EUI = 3,832,000,000 Btu/yr./45,000 sq. ft
= 85,156 Btu/sq. ft/yr. which is
less than the average office building
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, 8 Solutions Manual for Guide to Energy Management
Problem: The office building in Problem 1.6 pays $65,000 a year for
electric energy and $3,300 a year for fuel oil. Determine the
Energy Cost Index (ECI) for the building and compare it
to the ECI for an average building.
Solution: ECI = ($65,000 + $3,300)/45,000 sq. ft
= $1.52/sq. ft/yr.
which is greater than the average building
Process Engineering Channel
@ProcessEng
By Capehart, Chapter 1-13
SOLUTION MANUAL
, Table of Contents
Chapter 1: Introduction to Energy Management .................................. 1
Chapter 2: The Energy Audit Process: An Overview ........................ 15
Chapter 3: Understanding Energy Bill .................................................. 21
Chapter 4: Economic Analysis and Life Cycle Costing ..................... 37
Chapter 5: Lighting ................................................................................... 53
Chapter 6: Heating, Ventilating, and Air Conditioning .................... 69
Chapter 7: Combustion Processes and the
Use of Industrial Wastes ...................................................... 83
Chapter 8: Steam Generation and Distribution................................. 103
Chapter 9: Control Systems and Computers ......................................111
Chapter 10: Maintenance ......................................................................... 119
Chapter 11: Insulation .............................................................................. 127
Chapter 12: Process Energy Management ............................................ 141
Chapter 13: Renewable Energy Sources and Water ........................... 149
Management Supplemental ......................................................................... 158
Process Engineering Channel
@ProcessEng
v
, Chapter 1
Introduction to Energy Management
Problem: For your university or organization, list some energy man-
agement projects that might be good “first ones,” or early
selections.
Solution: Early projects should have a rapid payback, a high prob-
ability of success, and few negative consequences (increas-
ing/decreasing the air-conditioning/heat, or reducing
lighting levels).
Examples:
Switching to a more efficient light source (especially
in conditioned areas where one not only saves with
the reduced power consumption of the lamps but also
from reduced refrigeration or air-conditioning load).
Repairing steam leaks. Small steam leaks become large
leaks over time.
Insulating hot fluid pipes and tanks.
Install high efficiency motors.
Process Engineering Channel
And many more
@ProcessEng
1
, 2 Solutions Manual for Guide to Energy Management
Problem: Again for your university or organization, assume you are
starting a program and are defining goals. What are some
potential first-year goals?
Solution: Goals should be tough but achievable, measurable, and
specific.
Examples:
Total energy per unit of production will drop by 10
percent for the first and an additional 5 percent the
second.
Within 2 years all energy consumers of 5 million British
thermal units per hour (Btuh) or larger will be sepa-
rately metered for monitoring purposes.
Each plant in the division will have an active energy
management program by the end of the first year.
All plants will have contingency plans for gas cur-
tailments of varying duration by the end of the first
year.
All boilers of 50,000 lbm/hour or larger will be exam-
ined for waste heat recovery potential the first year.
Process Engineering Channel
@ProcessEng
, Introduction to Energy Management 3
Problem: Perform the following energy conversions and calcula-
tions:
a) A spherical balloon with a diameter of ten feet is filled
with natural gas. How much energy is contained in
that quantity of natural gas?
b) How many Btu are in 200 therms of natural gas? How
many Btu in 500 gallons of 92 fuel oil?
c) An oil tanker is carrying 20,000 barrels of #2 fuel oil.
If each gallon of fuel oil will generate 550 kWh of
electric energy in a power plant, how many kWh can
be generated from the oil in the tanker?
d) How much coal is required at a power plant with a
heat rate of 10,000 Btu/kWh to run a 6 kW electric
resistance heater constantly for 1 week (16 8 hours)?
e) A large city has a population which is served by a
single electric utility which burns coal to generate
electrical energy. If there are 500,000 utility customers
using an average of 12,000 kWh per year, how many
tons of coal must be burned in the power plants if the
heat rate is 10,500 Btu/kWh?
f) Consider an electric heater with a 4,500 watt heating
element. Assuming that the water heater is 98% effi-
cient, how long will it take to heat 50 gallons of water
from 70 degree F to 140 degree F?
Process Engineering Channel
@ProcessEng
, 4 Solutions Manual for Guide to Energy Management
Solution:
a) V = 4/3 (PI) P
= 4/3 × 3.14 × 53
523.33 ft3
E = V × 1,000 Btu/cubic foot of natural gas
= 523.33 ft3 X 1,000 Btu/ft3
= 523,333 Btu
b) E = 200 therms × 100, 000 Btu/therm of natural gas
= 20,000,000 Btu
E = 500 gallons × 140,000 Btu/gallon of #2 fuel oil
70,000,000 Btu
c) E = 20,000 barrels × 42 gal./barrel × 550 kWh/gal.
4.6E+08 kWh
d) V = 10,000 Btu/kWh × 6 kW × 168 h/25,000,000
Btu/ton coal
= 0.40 tons of coal
e) V = 500,000 cus. × 12,000 kWh/cus. × 10,500
Btu/kWh × I ton/25,000,000 Btu
= 2,520,000 tons of coal
f) E = 50 gal. × 8.34 lbm/gal. × (140F - 70F) ×
1 Btu/F/lbm
= 29,190 Btu
= 29,190 Btu/3,412 Btu/kWh
= 8.56 kWh
Process Engineering Channel
= 8.56 kWh/4.5 kW/0.98
= 1.94 h
@ProcessEng
, Introduction to Energy Management 5
Problem: If you were a member of the upper level management in
charge of implementing an energy management program
at your university or organization, what actions would you
take to reward participating individuals and to reinforce
commitment to energy management?
Solution: The following actions should be taken to reward individu-
als and reinforce commitment to energy management:
Develop goals and a way of tracking their progress.
Develop an energy accounting system with a perfor-
mance measure such as Btu/sq. ft or Btu/unit.
Assign energy costs to a cost center, profit center, an
investment center or some other department that has
an individual responsibility for cost or profit.
Reward (with a monetary bonus) all employees who
control cost or profit relative to the level of cost or
profit. At the risk of being repetitive, note that the level
of cost or profit should include energy costs.
Process Engineering Channel
@ProcessEng
, 6 Solutions Manual for Guide to Energy Management
Problem: A person takes a shower for ten minutes. The water flow
rate is three gallons per minute, the temperature of the
shower water is 110 degrees E Assuming that cold water
is at 65 degrees F, and that hot water from a 70% efficient
gas water heater is at 140 degrees F, how many cubic feet
of natural gas does it take to provide the hot water for the
shower?
Solution: E = 10 min × 3 gal./min × 8.34 lbm/gal ×
(110 F - 65 F) × 1 Btu/lbm/F
= 11,259 Btu
V = 11,259 Btu × 1 cubic foot/1,000 Btu/0.70
= 16.08 cubic feet of natural gas
Process Engineering Channel
@ProcessEng
, Introduction to Energy Management 7
Problem: An office building uses 1 Million kWh of electric energy
and 3,000 gallons of #2 fuel oil per year. The building has
45,000 square feet of conditioned space. Determine the
Energy Use Index (EUI) and compare it to the average EUI
of an office building.
Solution: E(elect.) = 1,000,000 kWh/yr. × 3,412 Btu/kWh
= 3,412,000,000 Btu/yr.
E(#2 fuel) = 3,000 gal./yr. × 140,000 Btu/gal.
= 420,000,000 Btu/yr.
E = 3,832,000,000 Btu/yr.
EUI = 3,832,000,000 Btu/yr./45,000 sq. ft
= 85,156 Btu/sq. ft/yr. which is
less than the average office building
Process Engineering Channel
@ProcessEng
, 8 Solutions Manual for Guide to Energy Management
Problem: The office building in Problem 1.6 pays $65,000 a year for
electric energy and $3,300 a year for fuel oil. Determine the
Energy Cost Index (ECI) for the building and compare it
to the ECI for an average building.
Solution: ECI = ($65,000 + $3,300)/45,000 sq. ft
= $1.52/sq. ft/yr.
which is greater than the average building
Process Engineering Channel
@ProcessEng
