1. Conservation of Energy
First Law of Thermodynamics
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2. True or False? Energy is conserved, only if no friction is present.
Energy can be converted from one form to another.
Work can be entirely converted to heat and vice versa.
An ideal heat engine that works with no friction is 100% efficient.
Construction of a time machine, although possible, must wait a very long time.
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3. Thermal Energy What is heat? Energy Conversion Efficiency Applications
Heat and Temperature
Energy Conversion
Conservation of Energy (1st Law)
Availability of Energy (2nd Law)
Efficiency
Applications
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4. Nature of Heat Historical Perspective Heat and Temperature
Aristotle (Phlogiston)
Lavoisier (caloric)
William Thompson (motion)
Heat and Temperature
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5. Temperature Conversion
Temperature Conversion Formula Following are the temperature conversion equations for converting degrees centigrade (C), fahrenheit (F), and kelvin (K).
F = 1.8 C (1)
C = (F – 32) / (2)
K = C (3)
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6. Modes of Heat Transfer Conduction Convection Radiation
Transfer of heat from molecule to molecule
Convection
Transfer of heat by bulk motion
Natural vs. Forced Convection
Radiation
Transfer of heat by electromagnetic waves.
Unlike conduction and convection, radiative heat transfer requires no medium.
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7. Electromagnetic Spectrum
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8. First Law of Thermodynamics
Historical Perspective
Richard Meyer
Kelvin
Joule
Energy Conversion
First law efficiency
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9. Energy Conversion Devices
EXAMPLES OF DIFFERENT KINDS OF ENERGY CONVERSIONS
FROM/TO
MECHANICAL
THERMAL
CHEMICAL
ELECTRICAL
LIGHT
Bicycle
Friction
Bomb
Wind generator
Sparks
Heat Engines
Heat exchanger
Pyrolysis
Thermo-couple
Luminescence
Rockets
Food
Metabolism
Fuel cell/ Battery
Candle
Electric Motor
Resistor
Electrolysis
Transformer
Light bulb
Galvanometer
Solar collector
Photosynthesis
Solar cell
Fluorescence
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10. Availability of energy
Second Law of Thermodynamics
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11. Second Law of Thermodynamics
Natural Direction and Arrow of Time
Entropy
Consequence of the Second law
Heat cannot, by itself flow from a low to a high temperature
Work can be completely converted to heat.
But heat cannot be completely converted to work.
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12. Why work is more valuable than heat?
True or false: Which one is better? An electric heater or a gas heater?
True or false: Which one is better? A gas hot water heater or a solar water heater?
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13. A very simple heat engine
A very simple heat engine. The air in (B) has been heated, increasing the molecular motion and thus the pressure. Some of the heat is transferred to the increased gravitational potential energy of the weight as it is converted to mechanical energy.

14. Heat Engines
A heat engine is any device that uses heat to perform work. No real engine can have an efficiency greater than that of a Carnot engine when both engines work between the same two temperatures.
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15. Claims, Lies and bigger lies
An engine manufacturer makes the following claims: The heat input of the engine is 9 kW at 375 K. The heat output is 4 kW at 225 K. Do you believe these claims?
hactual = 1 - Qc/Qh = 1- 4/9 = 0.56
Hideal = 1 - Tc/Th = /375 = 0.4
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16. Living Organisms
A living organism is an example of a heat engine which transforms light energy into chemical energy
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17. Hurricane
A hurricane is an elegant example of a natural Carnot heat engine. It draws heat from the ocean, releases some of it to the atmosphere via radiative cooling, and does work during this process.
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18. True or false: Heat can never flow from a cold reservoir to a hot one.
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19. True or false: A perfect engine produces no thermal pollution.
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20. Basic Elements of a Heat Engine
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21. Thermal Devices Internal Combustion Engines
Gasoline, diesel, and gas turbine
Refrigerator, Air Conditioners, and Heat Pumps
Thermal Powerplants
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22. Thermal Power Plants ENGR302I
1-2 Steam Turbine: High temperature, high pressure steam is expanded in a turbine. Work is produced in form of the shaft work. Turbine usually runs a generator to produce electricity,
2-3 Condenser: The output of the turbine is low temperature steam capable of doing little work. Steam is cooled in a condenser to liquid water, ready to be recycled to start another loop.
3-4 Feed Water Pump: Work is needed to pressurize water to the boiler pressure.
4-1 Boiler: Water is boiled and eventually heated to superheated steam. Fossil fuel, nuclear or other types of fuel can be used as a source of heating.
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23. Power Plant Operation (II)
According to the second law of thermodynamics, the higher the boiler pressure (temperature), and the lower the condenser temperature, the higher is the efficiency of the power plant.
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24. Power Plants Gasoline Engines Diesels Jet Engines
How does it work?
Power Plants
Gasoline Engines
Diesels
Jet Engines
Refrigerators and A/C
Heat Pumps
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25. How does a refrigerator work?
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26. If you leave your refrigerator door open, the temperature in the room will be...
Higher
Lower
The same
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27. How does a heat pump work?
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28. True or False? Energy is conserved, only if no friction is present.
Energy can be converted from one form to another.
Work can be entirely converted to work and vice versa.
An ideal heat engine that works with no friction is 100% efficient.
Construction of a time machine, although possible, must wait a very long time.
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