Course Overview

Review of Energy and Power

August 20, 2015

Session 01 components

• Review of course webpage

• Course objectives and outcomes

• Course organization, texts, assignments, etc.

• Energy and Power - Definitions and calibration

• Energy and Power - Consumption, present and future

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Learning Outcomes

•A review of some essential conceptso Energyo Power

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Value to participants

• It is critical to know the fundamental physics of energy, energy conversion, power, and power generation in this enterprise

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An Energy and Power PrimerA few words about units

The organization, SI, has established these “attachments” to simplify Scientific Notation

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Order of magnitude

SI name

109 Giga (G)

1012 Tera (T)

1015 Peta (P)

1018 Exa (E)

1021 Zetta (Z)

1024 Yotta (Y)

An Energy and Power Primer

A few words about energy and power:•Energy is a measurement of capacity to do work. It is expressed in units of Joules (J)

•Energy is expressed in two different forms:o Kinetic Energy – energy in motiono Potential Energy – energy in position

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Consider the pendulum

An Energy and Power Primer

• Energy is “conserved” – it is neither created nor destroyed. But it can be converted from one form to another

• Energy is also expressed in several different formats:o Optical Energyo Chemical Energyo Mechanical Energyo Thermal Energyo Electrical Energy

• Power is the rate at which energy is employed. It is expressed in units of Watts (W). One Watt equals one Joule per second

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An Energy Primer• The original units for energy and power came from thermal

scienceo One calorie (1 cal) is the energy required to raise one gram of

water by one degree Celsius (1oC)o One kilocalorie (1kcal) is the energy required to raise one

kilogram of water by one degree Celsius (1oC) – this is 1 food calorie

o One British Thermal Unit (1 BTU) is the energy required to raise one pound of water by one degree Fahrenheit (1oF)

o The most common unit for energy (work) in the scientific community is the Joule (J)

1 cal = 4.18 J

1 BTU = 1055 J

o The most common unit for energy in energy policy and engineering circles is the kilowatt-hour (kWh)

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An Energy Primero The most common unit for energy in energy

policy and engineering circles is the kilowatt-hour (kWh)

1 kWh = 1000W . 1hour = 1000W . 3600 sec = 3,600,000 W.sec = 3,600,000 J = 3.6MJ

o The energy content of fuels (like coal, oil) is usually quoted in BTUs

1 kWh = 3.6MJ .0.00095 J/BTU = 3412 BTU

o The BIG unit of energy measurement is the Quad:

1 Q = 1015 BTU = 2.93 x 1011 kWh = 293 TWh9

An Energy Primer - Calibration

• So what is the size of 1 kWh, in common, everyday values?

• Suppose Prof. Kozicki decides to go to Argentina and climb Mt. Aconcagua. How much potential energy does he gain during the climb?

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An Energy Primer

• Optical Energy is the energy contained in light; Optical Power is the rate at which optical energy is delivered.

• Chemical Energy is energy stored in atomic bonds, and in the motion or separation of ionic charges. The lead acid battery, or the AA dry cell, stores chemical energy.

• Mechanical Energy is the energy in moving or displaced objects at both microscopic and macroscopic scales. A spinning flywheel has kinetic mechanical energy; water stored behind a dam has potential mechanical energy.

• Thermal Energy refers to the energy associated with heat and its transfer

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An Energy Primer• Electrical Energy is the energy contained in electrons

and other charged particles; Electrical Power is the rate at which electrical energy is delivered to an “electrical load”

• Electrical Power is calculated by multiplying the Electrical Current and the Electrical Voltage in the electrical deviceo Current is a measure of the flow of electrons (amperes)o Voltage is a measure of the potential energy (volts)

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