Accepted Papers - 3.pdf - UNESCO

in power sector which is very difficult in developing
country like India.
It has been concluded by IEO2005 that the
developing countries mainly China and India will
be the major energy consumer in coming 10-15 years
due to the betterment in economy and rapid
infrastructural development. At present, the
changing phase of world economic policy i.e.
globalization, privatization and liberalization the
infrastructural development is going on in a very
rapid speed hence the energy demand is continuously
increasing. In developing countries like India every
sector is strongly being affected by energy policy of
the country. Therefore the gap between demand and
supply side is increasing. The traditional energy
sources also creating huge environmental pollutions
and causing greenhouse effect, ozone layer depletion
etc. India being a CDM (bounded by Kyoto Protocol)
country can not go through only coal based power
generation. Therefore alternating and environmental
friendly energy sources are very necessary for
sustainable development in the country like India.
Non-conventional energy resources can play an
important role in this direction.
3. Solar Energy : The Best Renewable Energy
Option for India
The sun is the largest source of renewable
energy and this energy is abundantly available in
all parts of the earth. It is in fact one of the best
alternatives to the non-renewable sources of energy.
One way to tap solar energy is through the use of
solar ponds. Solar ponds are large-scale energy
collectors with integral heat storage for supplying
thermal energy. It can be use for various applications,
such as process heating, water desalination,
refrigeration, drying and power generation.
Renewable energy is considered a suitable
alternative for variety of applications. Efforts are
continuously being stepped up on global basis to
harness renewable energy sources for the benefit of
peoples and also the society as a whole. In view of
this, solar energy technologies have attracted
significant attention of the researchers all over the
world. The sun is the primary source for most forms
of energy found on Earth. Solar energy is clean,
abundant, widespread, and renewable. These include
solar thermal as well as photovoltaic technologies
while the latter represents direct conversion of solar
374
energy into electricity, the former refers to the
applications where solar energy is used as heat. India
being a tropical country is blessed with good
sunshine over most parts, and the number of clear
sunny days in a year also being quite high. India is
in the sunny belt of the world. The country receives
solar energy equivalent to more than 5,000 trillion
kWh per year, which is far more than its total annual
energy consumption. The daily average global
radiation is around 5.0 k Wh/m 2 in northeastern and
hilly areas to about 7.0 kWh/m 2 in western regions
and cold dessert areas with the sunshine hours
ranging between 2300 and 3200 per year.
4. Solar Ponds
A solar pond refers to a segment (except
charging and discharging operations) large body of
water with black bottom and capable of collecting
and storing solar energy. The solar pond combines
solar energy collection and sensible heat storage.
Temperature inversions have been observed in
natural lakes having high concentration gradients
of dissolved salts (i.e. concentrated solution at
bottom and dilute solution at the top). This
phenomenon suggested the possibility of
constructing large-scale horizontal solar collectors
as ponds. Non-convective solar ponds have been
proposed as a simple relatively inexpensive method
of collecting and storing solar energy on a large
scale. The two most fundamental characteristics of
solar energy, namely its diluteness and intermittent
nature, are also the reasons why it is not being
harnessed on a large scale at present. The solar pond
works on a very simple principle. It is well-known
that water or air is heated they become lighter and
rise upward e.g. a hot air balloon. Similarly, in an
ordinary pond, the sun’s rays heat the water and the
heated water from within the pond rises and reaches
the top but loses the heat into the atmosphere. The
net result is that the pond water remains at the
atmospheric temperature. The solar pond restricts
this tendency by dissolving salt in the bottom layer
of the pond making it too heavy to rise.
A solar pond serves the dual purpose of
collection and storage of solar energy. In the solar
ponds, water is the medium for the storage and direct
absorption of solar radiation and solar pond is
categorized generally convective as well as nonconvective
ponds. Natural ponds convert solar