Техническое чтение для энергетиков. Бухарова Г.П. - 16 стр.

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18
night. The generation of electricity by batteries is still expensive but the advantage of
sun-powered lamps is that they can bring light to areas distant from any other power
supply.
There is one more advantage of solar power: not only it is unlimited, but also
its use does not pollute the environment. That is why it is very important to develop
devices which make it possible to transform solar power into mechanical or electric
forms of power.
ENERGY
In the language of science energy is the ability to do work. There are various
forms of energy, such as heat, mechanical, electrical, chemical, atomic and so on.
One might also mention the two kinds of mechanical energy–potential and kinetic,
potential energy being the energy of position while kinetic energy is the energy of
motion.
It is well known that one form of energy can be changed into another. A
waterfall may serve as an example. Water falling from its raised position, energy
changes from potential to kinetic energy. The energy of falling water is generally
used to turn the turbines of hydroelectric stations. The turbines in their turn drive the
electric generators, the latter producing electric energy. Thus, the mechanical energy
of falling water is turned into electric energy. The electric energy, in its turn, may be
transformed into any other necessary form.
When an object loses its potential energy, that energy is turned into kinetic
energy. Thus, in the above-mentioned example when water is falling from its raised
position, it certainly loses its potential energy, that energy changing into kinetic
energy.
We have already seen that energy of some kind must be employed to generate
the electric current. Generally speaking, the "sources of energy usually employed to
produce current are either chemical as in the battery, or mechanical, as in the
electromagnetic generator. Chemical sources of current having a limited application,
the great quantities of electric energy generated today come from various forms of
mechanical energy.
The rising standards of modern civilization and growing industrial application of
the electric current result in an increasing need of energy. Every year we need more
and more energy. We need it to do a lot of useful things that are done by electricity.
However, the energy sources of the world are decreasing while the energy needs of
the world are increasing. These needs will continue to grow as more motors and
melted metals are used in industry and more electric current is employed in everyday
life. As a result, it is necessary to find new sources of energy.
The sun is an unlimited source of energy. However, at present, only a little part
of solar energy is being used j directly. How can we employ solar energy directly
to produce useful energy? This is a question which has interested scientists and
inventors for a long time. Lavoisier and other great scientists of the past melted
metals with the help of solar furnaces. Today, solar furnaces illustrate just one of the

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