Microphone!

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Microphone!
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Energy What it is, how we use it, how we waste
it
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Which would you prefer to do? Stick your hand in
boiling water or steam?
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What is Energy?
Energy is the amount of work a physical system is
capable of performing so energy can be defined as
that which changes the position, physical
composition or temperature of an object
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Energy comes in many flavors
Form What it is or does Example
Mechanical Motion kinetic or potential Moving car, coyote poised to fall
Chemical Potential energy in molecular bonds Fossil fuels, food, explosions
Thermal Internal temp. of substances Hot water, steam, body temperature
Electrical Electrons moving across potentials Electric circuits, batteries, fuel cells
Radiant Electromagnetic light, heat Sunlight, heat emitted by objects
Nuclear Potential energy in atomic nucleus Nuclear fission fusion
Gravitational Energy of place or position Hydroelectricity, falling coyote
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We tend to transform energy in order to make it
usable

• We burn fossil fuels to generate usable heat
  energy to make steam to turn electrical turbines
• We split atomic nuclei to do the same thing
• We burn gasoline to create energetic gases that
  push pistons in internal combustion engines
• We transform liquids and gases moving at high
  velocities into rotational kinetic energy that
  turns shafts for various purposes

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Energy is measured in many different units
BTUs
Kilowatt-hours
Gallons
Barrels
Kilocalories (equals one food calorie
Therms
Calories
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Energy densities vary a great deal
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1 milllion BTU equals approximately

• 90 lbs of butuminous coal and lignite production
• 125 lbs of oven-dried wood
• 8 gallons of gasoline (enough to move an average
  passenger car 150-200 miles)
• 10 therms of dry natural gas
• 11 gallons of propane
• 2 months of dietary intake of a laborer
• 20 cases (240 cases) of table wine

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You are a lightbulb (not a walrus), and as much
as 10 C batteries
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Power is a measure of the rate of energy
production and consumption
A typical 100 watt light bulb consumes 100 watts
of energy per hour (0.1 kWh)
A standard 1 GWe (gigawatt) nuclear power plant
generates a billion watts of electrical energy
per hour (1 million kilowatt-hrs)
A 150 horsepower car that gets 30 mpg, driven at
60 mph, consumes 2 gal/hr of gasoline 2 gallons
of gasoline contain about 73 kWh or 98 hp-hr of
energy.
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To use energy more efficiently, it helps to match
power rates to requirements
Because an automobile has highly variable power
requirementsfrom 1 mph to bursts of 80 mph, it
requires a high peak power capacitywhich is
difficult to provide with electricity and which
tends to lower the efficiency of energy use
By contrast, a vehicle that only needs a maximum
speed of 30 mph also requires much variability in
velocity and acceleration rates, and less peak
power capacity (that is why hybrids rely much
more on electric power system for local travel)
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Meanwhile, we value energy for the services it
can provide, not for its specific form
We burn fuel at 1,000 degrees to boil water at
212 to make a hot drink at 120 which we radiate
as body heat at 98.6
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Basic principle of energy use we take high
quality energy sources, use them to do work for
us, and degrade them into lower-quality heat
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Someday, all energy sources in the universe will
probably dissipate as very low quality heat
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House as an energy eco-system energy goes in,
does work, becomes heat, and escapes at lt70
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Houses are only one type of energy ecosystem

• There are various ways to increase the efficiency
  of energy use on both supply and demand sides
• in the generation process
• in matching source to need (e.g., solar for
  heating water space)
• in more efficient combustion distribution
  systems
• in demand reduction through more efficient
  appliances, insulation, leak reduction, etc.

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Saving energy in the household

1. Set your thermostat lower
2. Dont heat the whole house
3. Wash cloths with the Cold/Cold setting and use
   full loads
4. Unplug computers, TVs, Cable boxes, and other
   energy vampire appliances when not in use
5. Turn off the lights when you leave the room
6. Take shorter showers
7. Trim those bushes on the south side of your home
   and open the shades
8. Adjust water heaters down to 126 degrees
9. Clean heater and refrigerator filters vents to
   maximize performance
10. Cook more efficiently

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What is your consumption profile?
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