02-11-2010, 01:43 PM
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Air Conditioners
Observations AboutAir Conditioners
They cool room air on hot days
They emit hot air from their outside vents
They consume lots of electric power
They are less efficient on hotter days
They can sometimes heat houses, too
Heat Machines
Air conditioners
use work to transfer heat from cold to hot
are a type of heat pump
Automobiles
use flow of heat from hot to cold to do work
are a type of heat engine
Thermodynamics
Rules governing thermal energy flow
Relationships between
thermal energy and mechanical work
disordered energy and ordered energy
Codified in four laws of thermodynamics