Energy
principles  |
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Basic
Energy Principles
Energy is the driving force for the universe. Energy is a
quantitative property of a system which may be kinetic, potential,
or other in form. There are many different forms of energy.
One form of energy can be transferred to another form. The
laws of thermodynamics govern how and why energy is transferred.
Before the different types of energy resources and their uses
are discussed, it is important to understand a little about
the basic laws of energy. |
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The
Three Laws of Thermodynamics 
- The
first law of thermodynamics, also called conservation
of energy, states that the total amount of energy in the universe
is constant. This means that all of the energy has to end
up somewhere, either in the original form or in a different
from. We can use this knowledge to determine the amount of
energy in a system, the amount lost as waste heat, and the
efficiency of the system. |
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-The second law of
thermodynamics states that the disorder in the universe always
increases. After cleaning your room, it always has a tendency
to become messy again. This is a result of the second law.
As the disorder in the universe increases, the energy is transformed
into less usable forms. Thus, the efficiency of any process
will always be less than 100%. |
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The third law of thermodynamics tells us that
all molecular movement stops at a temperature we call absolute
zero, or 0 Kelvin (-273oC). Since temperature is
a measure of molecular movement, there can be no temperature
lower than absolute zero. At this temperature, a perfect crystal
has no disorder.
When put together, these laws state that a concentrated energy
supply must be used to accomplish useful work. |
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Work
Many of us commonly think of energy as the ability of a system
to do work. Work is a force applied to an object over a certain
distance, such as pulling or pushing a wooden block across
your desk. Your muscles do work when they facilitate body
movement. Units of work and energy are joules (J). One joule
equals one Newton meter (N*m). |
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By
definition, work is an energy requiring process. So, how do
you describe energy? Energy is not a substance that can be
held, seen, or felt as a separate entity. We cannot create
new energy that is not already present in the universe. We
can only take different types materials in which energy is
stored, change their state, and harness the energy that escapes
from the system in order to use it to do work for us. If the
released energy is not used, it will escape and be "wasted"
usually as heat. |
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