power and energy advanced design applications power and energy © 2014 international technology and...

Advanced Design Applications

Power and EnergyPower and Energy

© 2014 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Advanced Design Applications

Teacher Resource Unit / Lesson Learning Cycle One

Learning Cycle One – Introduction to Measurement and Energy

MeasurementsMeasurements

Measurements, in order to be precise, must have a standard, which ensures that all measurements are alike.

A measurement standard is an exact quantity that people agree to use for comparison.


Measurements - 1Measurements - 1

Measurements must have units Units are what you use to measure the

object – our system has units such as feet, inches, and pounds.

SI units – SI stands for Le Systeme Internationale d'Unites The SI units are universally accepted and

understood by scientists throughout the world.



Prefixes in SI tell you what part of a base unit is represented milli – 1/1,000 or 0.001 of a unit

Ex. millimeter = 1/1,000 of a meter centi – 1/100 or 0.01 of a unit Ex. centimeter = 1/100 of meter deci – 1/10 or 0.1 of a unit Ex. decimeter = 1/10 of a meter deca – 10 times a unit Ex. decameter = 10 meters


Windows User

changed - to = and eliminated - after "unit" so easier to readAlso eliminated bullets before examples


hecto – 100 times a unit Ex. hectometer = 100 meters kilo – 1,000 times a unit Ex. kilometer = 1,000 meters

Derived units – units obtained by combining different units, such as

cm3 and g/mm3


Windows User

Changed from cm3 so there isn't confusion trying to relate to cm3 which is itself a derived unit

Types of MeasurementsTypes of Measurements

Types of measurements include length, volume, mass and density Length – distance between two points Volume – the amount of space an object takes up Mass – all of the matter contained in a material Density – mass per unit volume Temperature – two temperatures; Celsius, used for

most laboratory work and Kelvin, which is based on absolute zero which is the coldest temperature possible. 0 K is equal to -273 C.


Engineering NotationEngineering Notation

Measurement for EnergyMeasurement for Energy

Unit for energy is a Joule 1 Joule = 1 newton-meter


Measurement for PowerMeasurement for Power

Power can also be measured in kilowatts. The watt is such a small amount of power that many times kilowatts are used instead.

1 kW = 1000 watts


Section 2Section 2

Types of Energy


What is Energy?What is Energy?

Energy is the ability to produce change or to do work.

Types of energy that we will learn about are: kinetic, potential, and total energy.


Types of EnergyTypes of Energy

The total energy in a substance or a system is the sum of the kinetic, potential and internal energies.


Conservation of EnergyConservation of Energy

The law of conservation of energy states that energy may change from one form to another, but the total amount of energy never changes.

*1st Law of Thermodynamics* Example: swing or pendulum. As the

swing moves back and forth the energy is continually converted from kinetic to potential energy.


Kinetic EnergyKinetic Energy

Kinetic energy is energy in the form of motion. The amount of kinetic energy depends on the mass of the object and its velocity.

Formula: Kinetic Energy (KE) = ½ mass (½ m) x velocity2 (v2) Units:

• Mass = kg • Velocity = m/s • Energy = Joule (J)


Potential EnergyPotential Energy

Potential energy is energy stored in a motionless object due to its position or condition.

Gravitational potential energy (GPE) is energy stored in objects that are in a position above the ground and having stored energy due to the force of gravity. An example would be a ball held suspended above ground.


GPE Calculations GPE Calculations

The formula: Gravitation Potential Energy (GPE) is:

GPE = mass (m) x 9.8 m/s2 x (h) Units: Mass = kilograms (kg) Gravity = meters/second2 (m/s2) Energy = Joules (J)


Section 3Section 3

Sources of Energy


Six Sources of EnergySix Sources of Energy

Nuclear * fission or fusion Electromagnetic *communication Chemical *batteries, coal Mechanical *speeding trains Thermal *heat engine, refrigerator Electrical *lightning


Six Types of Energy SourcesSix Types of Energy Sources

Nuclear - Energy released when the nuclei of atoms are split or fused.

Electromagnetic - Energy that travels through space in the form of waves.

Chemical- Energy stored within the bonds between molecules.


Six Types of Energy SourcesSix Types of Energy Sources

Mechanical- Energy of motion Thermal- Energy of moving or

vibrating molecules. Electrical- Energy generated by

moving electrons.


Section 4Section 4

Electric Motors and Generators


Electric MotorElectric Motor

A device that changes electrical energy into mechanical energy.

An electric motor contains an electromagnet that is free to rotate between two poles of a fixed permanent magnet.

A - Power SourceB – ElectromagnetC – Permanent magnet


GeneratorGenerator

Generator does just the opposite of an electric motor.

Changes mechanical energy into electrical energy.

Uses electromagnetic induction by turning a coil of wire in a strong magnetic field.


Section 5Section 5

Chemical Energy Battery


Chemical Energy BatteryChemical Energy Battery

Combination of cells that provide chemical energy.


Chemical Energy BatteryChemical Energy Battery

PRIMARY CELLS VS. SECONDARY CELLS The basic difference is recharging ability. Primary cells - cannot be recharged after rated

capacity is delivered. *must be discarded because the chemical reaction cannot be restored*

Secondary cells or storage cell - the chemical reaction is reversible.


Chemical Energy Battery Chemical Energy Battery Carbon-Zinc Dry CellCarbon-Zinc Dry Cell

Most common dry cell Operates at temperature of 70ºF. Higher

temperatures will enable the cell to provide greater output. However, temperatures above 125ºF will cause rapid deterioration.

Self-discharge of the cell when not in use reduces life (lower shelf life).

Shelf life can be extended when stored at 40-50ºF. But, the battery should be allowed to return to room temperature before use.


Chemical Energy Battery Chemical Energy Battery Alkaline CellAlkaline Cell

Can be a primary or secondary cell. Has a high discharge rate. 2x life of carbon-zinc in a transistor

radio. 7x life in toys. Outstanding performance is due to

low internal resistance. Performs well at lower temperatures. Shelf life is better than carbon-zinc.


Chemical Energy- BatteryChemical Energy- BatteryMercury*Silver Oxide*Zinc Mercury*Silver Oxide*Zinc ChlorideChloride

MercuryHigh costGood operation at high temperatures (130ºF continuous, 200ºF short)Silver OxideUsed in hearing aids, cameras, watches Zinc ChlorideSimilar to carbon-zinc, but can deliver more current over a longer time


Chemical Energy Chemical Energy Battery - LithiumBattery - Lithium

High output voltage long shelf life low weight small volume 10x energy of carbon-zinc Uses- Pacemakers


Chemical Energy Battery- Lead AcidChemical Energy Battery- Lead Acid

Ideal for high values of load current are required.

Charge and discharge can be repeated.

Heat with excessive charge and discharge currents shortens the useful life of the battery.

Uses - Car batteries


Chemical Energy Battery- Chemical Energy Battery- Nickel CadmiumNickel Cadmium

Ideal for high load current applications.

Can be cycled many times (recharging)

Can be stored when discharged for a long time without damage.


Non-renewable Renewable

Section 6Section 6Non-renewable vs. RenewableNon-renewable vs. Renewable


Nonrenewable EnergyNonrenewable Energy

Coal Petroleum Natural gas Propane Uranium


Renewable EnergyRenewable Energy

Biomass Geothermal Hydropower Solar Wind


GeothermalGeothermal

Geothermal - Thermal energy beneath the earth’s surface


WindWind

Kinetic energy from horizontal wind into the turbine’s axle.


Wind Turbine GeneratorsWind Turbine Generators The generator is attached at

one end to the wind turbine, which provides the mechanical energy.

At the other end, the generator is connected to the electrical grid.

Wind power generators convert wind energy (mechanical energy) to electrical energy.

The generator needs to have a cooling system to make sure there is no overheating.


Large GeneratorsLarge Generators

Very efficient at high wind speeds, unable to turn at low wind speeds.

If the generator has larger coils, and/or a stronger internal magnet, it will require more mechanical force to over come static friction.


Wind Turbines: Number of Blades Wind Turbines: Number of Blades Most common design is the three-bladed turbine - most

stable turbine A rotor with an odd number of rotor blades (and at least

three blades) can be considered to be similar to a disc when calculating the dynamic properties of the machine.

A rotor with an even number of blades will give stability problems for a machine with a stiff structure. The reason is that at the very moment when the uppermost blade bends backwards, because it gets the maximum power from the wind, the lowermost blade passes into the wind shade in front of the tower.


Solar Photovoltaic CellsSolar Photovoltaic Cells

Photovoltaic systems convert radiant energy directly into electricity.


Solar Photovoltaic CellsSolar Photovoltaic Cells Solar cells are made of the same kinds of semiconductor

materials, such as silicon, used in the microelectronics industry. A thin semiconductor wafer is specially treated to form an electric field, positive on one side and negative on the other. When light energy strikes the solar cell, electrons are knocked loose from the atoms in the semiconductor material.


Solar Photovoltaic CellsSolar Photovoltaic Cells

Multiple modules can be wired together to form an array. In general, the larger the area of a module or array, the more electricity that will be produced. Photovoltaic modules and arrays produce direct-current (dc) electricity. They can be connected in both series and parallel electrical arrangements to produce any required voltage and current combination.


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