today's climate of growing energy needs and increasing
environmental concern, alternatives to the use of non-renewable
and polluting fossil fuels have to be investigated. One such
alternative is solar energy.
energy is quite simply the energy produced directly by the sun
and collected elsewhere, normally the Earth. The sun creates its
energy through a thermonuclear process that converts about
650,000,000 tons of hydrogen to helium every second. The process
creates heat and electromagnetic radiation. The heat remains in
the sun and is instrumental in maintaining the thermonuclear
reaction. The electromagnetic radiation (including visible
light, infra-red light, and ultra-violet radiation) streams out
into space in all directions.
very small fraction of the total radiation produced reaches the
Earth. The radiation that does reach the Earth is the indirect
source of nearly every type of energy used today. The exceptions
are geothermal energy, and nuclear fission and fusion. Even
fossil fuels owe their origins to the sun; they were once living
plants and animals whose life was dependent upon the sun.
the world's required energy can be supplied directly by solar
power. More still can be provided indirectly. The practicality
of doing so will be examined, as well as the benefits and
drawbacks. In addition, the uses solar energy is currently
applied to will be noted.
the nature of solar energy, two components are required to have
a functional solar energy generator. These two components are
a collector and a storage unit. The collector simply collects
the radiation that falls on it and converts a fraction of it to
other forms of energy (either electricity and heat or heat
alone). The storage unit is required because of the non-constant
nature of solar energy; at certain times only a very small
amount of radiation will be received. At night or during heavy
cloud cover , for example, the amount of energy produced by the
collector will be quite small. The storage unit can hold the
excess energy produced during the periods of maximum
productivity, and release it when the productivity drops. In
practice, a backup power supply is usually added, too, for the
situations when the amount of energy required is greater than
both what is being produced and what is stored in the container.
collecting and storing solar energy vary depending on the uses
planned for the solar generator. In general, there are three
types of collectors and many forms of storage units.