Page 43 - Alternative Energy Systems in Building Design

20 ENERGY SYSTEMS

■ In earth sciences, continental drift, volcanic activity, and earthquakes are phenomena
that can be explained in terms of energy transformation in the earth’s interior.
Meteorologic phenomena such as wind, rain, hail, snow, lightning, tornados, and
hurricanes are all a result of energy transformations brought about by solar energy.

Energy transformations in the universe are characterized by various kinds of potential
energy that have been available since the Big Bang and later “released” to be trans-
formed into more active types of energy.

NUCLEAR DECAY
Examples of such processes include those in which energy that was originally “stored”
in heavy isotopes such as uranium and thorium is released by nucleosynthesis. In this
process, gravitational potential energy, released from the gravitational collapse of
supernovae, is used to store energy in the creation of these heavy elements before their
incorporation into the solar system and earth. This energy is triggered and released in
nuclear fission bombs.

FUSION
In a similar chain of transformations at the dawn of the universe, the nuclear fusion of
hydrogen in the sun released another store of potential energy that was created at the
time of the Big Bang. Space expanded, and the universe cooled too rapidly for hydrogen
to fuse completely into heavier elements. Hydrogen thus represents a store of potential
energy that can be released by nuclease fusion.

SUNLIGHT ENERGY STORAGE
Solar power energy when converted to electricity can be used to pump water from
lower body of water into a hydroelectric dam or reservoir stored again as gravitational
potential energy. After being released at a hydroelectric dam, this water can be used
to drive turbines and generators to produce electricity. Sunlight also drives all weather
phenomena, including such events as hurricanes, in which large, unstable areas of
warm ocean, heated over months, suddenly give up some of their thermal energy to
power intense air movement.

KINETIC VERSUS POTENTIAL ENERGY
An important distinction should be made between kinetic and potential energy before
continuing. Potential energy is the energy of matter owing to its position or arrange-
ment. This stored energy can be found in any lifted objects, which have the force of
gravity bringing them down to their original positions. Kinetic energy is the energy
that an object possesses owing to its motion. A great example of this is seen with a ball
that falls under the influence of gravity. As it accelerates downward, its potential energy
is converted into kinetic energy. When it hits the ground and deforms, the kinetic