PhD Research Thesis on Renewable Energy Sample

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RENEWABLE ENERGY
SAMPLE
a very important role in reducing carbon dioxide emissions into the atmosphere, increasing the
share of renewable energy increases the energy sustainability of their compounds, helping them to
improve energy security by reducing dependence on imports of energy raw materials and
electricity. The process of accepting new technologies is very slow. The main problem with installing
new plants is the starting price. This increases the cost of energy received in the first few years, to
the level of complete unreliability in relation to other commercially available energy sources. The
large share in the production of energy from renewable sources is a result of the ecological
awareness of the population, which, despite the initial economic failure, installs plants for the
production of "clean" energy. The use of renewable energy sources for the production of electricity
and heat should be distinguished. For now, only hydropower has a significant share in the
production of electricity, although in the last years the wind energy that is approaching
commercialization. The sun is our closest star and, directly or indirectly, the source of almost all
available energy on Earth. The Sun's energy comes from nuclear reactions in its center. It is a fusion,
in which the formation of helium occurs by the coupling of hydrogen atoms, with the release of a
large amount of energy. Every second, in this way, helium exceeds 600 million tons of hydrogen,
and the mass of some 4 million tons of hydrogen is converted into energy. This energy, in the form
of light and heat, is expanding into the Universe, so a small part comes to the Earth. Nuclear fusion
takes place in the Sun for about 5 billion years, its estimated age, and according to the available
hydrogen stock, it can be calculated that it will continue for about 5 billion years. Under optimal
conditions, approximately 1 kW / m2 of insolation can be obtained on the Earth's surface and the
actual value depends on location, season, time of day, weather conditions, etc. The temperature in
the center is not the temperature that determines the electromagnetic properties of the Sun's
radiation, because the radiation from the interior in large part absorbs the ion layer near the surface.
The Sun's radiation spectrum closely corresponds to the black body's spectrum at a temperature of
5760 K. Therefore, the temperature of 5760 K can be taken as the effective temperature of the Sun's
surface. By using the Plan's Law, it is possible to calculate the energy spectrum of the Sun's
radiation. The radiation from the surface of the Sun is about 9.5 "1025 W, and the radiation consists
of different wavelengths. The spectrum of electromagnetic Sun radiation consists of an ultraviolet,
visible and infrared part. The ultraviolet part carries about 9%, visible about 41.5% and infrared
about 49.5% of the total energy of the Sun's radiation (Ben, 2000).
The basic principles of direct use of solar energy are: passive techniques - solar collectors
(converting solar energy into heat); photovoltaic cells (direct conversion of solar energy into
electrical energy); focusing on solar energy (for use in large power plants) (Aldo, 2008). The solar
space heating system can be passive, active, or a combination of passive and active. Passive is
usually cheaper and simpler than active ones. However, the passive use of solar energy must be
taken into account when building a house. The most famous example of passive use of solar energy