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ISAT 413 ─ Module I: Introduction to Energy Efficiency

Topic 1: Trends in the Energy Industry and Introduction to Energy Efficiency

Reading and HW Assignments:(See “Assignments” on the Blackboard)

• Course Pack Module I

• Web readings are also posted on the Blackboard / assignments site

Energy for America’s Future

Protecting the Environment through Energy Efficiency

Making Homes more Energy Efficient

Maintaining Energy for the Future

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• First week reading assignment:(The following 4 articles will to be discussed in our next class)• Easy on The Gas (Mechanical Engineering, July 2006)

http://www.memagazine.org/contents/current/features/easygas/easygas.html

• Juiced Up (Mechanical Engineering, July 2006) http://www.memagazine.org/contents/current/features/juicedup/juicedup.html

• Beginning the Transformation (Mechanical Engineering, May 2006) http://www.memagazine.org/backissues/may06/features/beginthe/beginthe.html

• Efficiency is Its Own Reward (Mechanical Engineering, March 2006) http://www.memagazine.org/backissues/mar06/features/effncy/effncy.html

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Gasoline price board at a Chevron gas station in San Francisco on Wednesday, Aug. 23, 2006. Oil prices zoomed higher Wednesday, touching a new high of $73 a barrel. Is hybrid a solution?

Blackout: At 4:11 p.m. ET on Aug. 14, 2003, Ontario and much of the northeastern U.S. were hit by the largest blackout in North America's history. Electricity was cut to 50 million people, bringing darkness to customers from New York to Toronto to North Bay.

Current Energy Issues

Energy Bill Signed: On July 29, 2005, Congress passed the first comprehensive energy legislation in over a decade.

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Introduction

• In the first half of the 20th century, energy sources were exploited with the primary consideration given to economics ─ low cost.

• In the third quarter of the 20th century, the power engineer had to concerned with the three “E’s” of energy conversion ─ energy, economy, and ecology.

• During the final quarter of the 20th century, the power engineer is further burdened and must be concerned with the six “P’s” of energy conversion ─ power, pennies, pollution, politics, prejudice, and public relations.

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Energy, Mass, and Power Units• In 1922, Albert Einstein hypothesized that energy and

mass are actually related according to 2mcE Where E is the energy release, in joules, m is the actual mass converted into energy, in kilograms, and c is the velocity of light (3108 m/s).

• Units:

Energy: joule (J), electron volts (eV), British thermal units (Btu), foot-pound force (ft.lbf), watthour (Wh), kWh, horsepower-hour (hph).

Power (energy rate): W, kW, MW, GW (gigawatts), TW (terawatts, 1.01012 W), hp, J/s, Btu/h.

Mass: kg, lbm, amu (atomic mass unit), tons, tonnes, g.

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Example: Energy Released in the Fission of 235U

kWh.eV

g/molA

mol/nuclei.N

25

23

1044401

235

10026

number, mass Uranium

number, sAvogadro'

:Given

Calculate the total energy (in kWh) released if 1.00 kg of 235U undergoes fission, taking the disintegration energy per event to be Edisint. = 208 MeV. (Ans: 2.37107 kWh)

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Energy Types and Classifications

• Types:

Transitional ─ energy in motion and can move across system boundaries

Stored ─ can exist as mass and position of a substance in a field

• Classifications:

Mechanical ─ can be used to raise a weight.

Electrical ─ flow or accumulation of electrons.

Electromagnetic ─ pure energy with no mass

Chemical ─ electron interactions among molecules.

Nuclear ─ particle interactions within atomic nucleus.

Thermal ─ energy associated with atomic and molecular vibration.

.hvE

2

2

1

3

2vm

kT

B

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Energy Sources

Income energy (energy sources reaching the earth from outer space which are continuing and nondepletable):

• Direct solar energy, biomass (includes trees, animals, plants, organic wastes, etc.), ocean thermal energy conversion (OTEC), lunar (gravitational energy from the moon) tidal energy.

Capital energy (already exists on or within the earth):

• Fossil fuel is the major capital energy source (90% in U.S., the other 10% is primarily hydroelectric and nuclear power), geothermal (hydrothermal and petrothermal which have pollution and seismic problems?)

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Energy Reserves

The energy reserves of the earth can be divided into four general categories. These include renewable or nondepletable, fossil fuels, fissionable and fertile materials, and fussionable isotopes.

The amount of energy reserves is strongly dependent on the current market price of raw energy. This is particular true for nonrenewable energy reserves such as shale oil, oil, and uranium.

As the cost of energy increases, it becomes profitable to mine the low-grade ores and resort to secondary and tertiary recovery methods for the production of petroleum. This effectively increases the usable reserves.

(See Table 1.1 of Course Pack Module I)

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Energy Utilization

The Production and Consumption of Energy in The United States

Realizing how the principal source of fuel energy has changed over the years, it is interesting to speculate as just what the primary source of fuel energy will be in the year 2050. Solar or Fission?

Year

Energy Production by Types of Fuel (%)

CoalNatural

GasCrude

Oil NuclearRenewable Total

1955 31 26 36 0 7 100

1975 24 36 29 3 8 100

1995 31 30 20 10 9 100

2005 33 30 16 12 9 100

Energy Consumption by End-Use Sector (%)

Residen. Commer. Indust. Transport. Total Electr.

18 10 48 24 100 16

21 13 41 25 100 28

20 16 37 26 100 37

22 18 32 28 100 40

(Data source: http://www.eia.doe.gov/emeu/aer/ep/ep_text.html)

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Electrical Power Generation and Consumption

• The electrical power generation in the U.S. for the year 1970 totaled 1.621012 kWh. The total installed capacity was 356,000 MWe (average capacity factor for electrical grid was about 50%).

• The prime sources for the production of electricity were as follows: 6.3% from oil, 22.0% natural gas, 52.5% coal and lignite, 18.2% hydro, and 1.0% from nuclear.

• By 1975, the installed nuclear capacity had risen to almost 8%, and 100 nuclear plants were in operation in the U.S. by 1986.

• The primary sources of fuel energy for the production of electricity during 20th century are coal, nuclear and hydro. What would they be for the 21st century?

(See Figure 1.7 of Course Pack Module I)

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Power Generation Terminology

• Power density — power per unit volume (kW/m3).

• Specific power — power per unit mass of fuel (kW/kg fuel).

• Cogeneration ( formerly called in-plant generation, byproduct generation) — the production of electricity along with other useful energy forms, such as process heat or steam, at the same location.

The terminology associated with electric-power generation can be divided into three basic categories namely:

• Power system performance factors,

• types of power generation systems, and

• economic factors.

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Power Systems Performance Factors• Thermal efficiency, th — The ratio of output energy to input energy (dimensionless).

• Heat rate — 3412/th (Btuth / kWeh).

• Capacity factor — The ratio of average power of a generating system to the rated power over a given time interval (for power generating systems).

• Load factor — The ratio of the average power to the maximum power for a given system over the same time interval (for power users or consumers).

• Availability factor — The fraction of a particular time interval that the system is available for power generation.

• Spinning reserve — Excess capacity that is running and synchronized with the system.

• Reserve capacity — The difference between the total rated capacity of all the units in the grid and the expected peak load or demand on the system, usually +20%.

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Types of Power Systems

• Based-load power plants — Those systems that average more than 5000 full-power hours per year (capacity factor > 57%). Typically have high rated output, low operating costs. Coal-fired and nuclear power plants.

• Intermediate-load power systems — Power plant that average more than 2000 but fewer than 5000 full-power hours per year (23% < capacity factor < 57%). Older, less-efficient power plants. Oil-fired and new combined-cycle units.

• Peaking power systems — Units that are operated only to meet the power demands at time of maximum demand, usually during the summer in the South and during the winter in the North, usually less than 2000 full-power hours per year (capacity factor < 23%). High operating costs. Combustion turbines, diesel engines, and pumped-storage units are commonly employed as peaking units.

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Power Economic Terminology

• Depreciation — The amount of plant investment that can be written off as part of the annual operating costs.

• Rate base — The sum value of all the capital and operating assets of that utility, from the largest power plant to the smallest roll of wire.

• CWIP — An acronym for “Construction Work in Progress” and pertains to interest paid on the money borrowed to build the power plant.

• AFUDC — An acronym for “Allowance for Funds Used During Construction.” Typically requires the utility to seek rate increases of 30 to 60%. When these increases go into effect, it commonly produces an effect called rate shock.

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Some Typical Operational Efficiencies of Energy-Conversion Systems

(See Figure 1.10 of Course Pack Module I )

• Hydroelectric installation: ~90%, from mechanical potential energy to mechanical work , and then to electricity.

• Large coal-fired boiler: ~83%, from chemical energy to thermal energy.

• Hydrogen-oxygen fuel cell: ~58%, from chemical energy to electricity.

• Automobile alternator (generator): ~48%, from mechanical work to electricity.

• Fossil-fueled steam power plant: ~40%, from chemical to thermal energy, to mechanical work, and then to electricity.

• Fluorescent light: ~18%, from electricity to electromagnetic energy.

• Incandescent light: ~4%, from electricity to electromagnetic energy.