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“Light to electrical energy:
When sunlight falls on a solar photovoltaic panel it generates electricity
in the form of direct current. This is stored in the battery bank.
Whenever we need this stored energy it is drawn from the battery
through a high efficiency inverter to get AC power useful for our home.
This is an indirect form of solar energy usage.

Heat to thermal energy:
When sunlight falls on a thermal collector the heat is directly
transferred to the liquid (mostly water) and stored in the hot water tank
which is insulated to avoid heat loss. The hot water can be drawn and
used when ever required. This is a direct form of solar energy usage.”

         Chapter 2 - Solar energy harnessing – How it works

“A thin-film solar cell is a solar cell that is made by depositing one or
more thin layers of photovoltaic material on a substrate. The thickness
range of such a deposition layer is wide and varies from a few
nanometers to tens of micrometers. Since the PV cell is made with a
microscopically thin deposit of silicon instead of a thick wafer, it would
use very little of the precious material. It is deposited on a sheet of
metal or glass, without the wasteful work of slicing wafers with a saw.
The individual cells are deposited next to each other, instead of being
mechanically assembled. This is the structure of thin film technology. (It
is also called amorphous, meaning "not crystalline".)

Charge regulation: This is the primary function of a battery charge
controller, and perhaps the single most important issue related to
battery performance and life. The purpose of a charge controller is to
supply power to the battery in a manner which fully recharges the
battery without overcharging. Without charge control, the current from
the array will flow into a battery proportional to the irradiance, whether
the battery needs charging or not. If the battery is fully charged,
unregulated charging will cause the battery voltage to reach
exceedingly high levels, causing severe gassing, electrolyte loss,
internal heating and accelerated grid corrosion. In most cases if a
battery is not protected from overcharge in PV system, premature
failure of the battery and loss of load are likely to occur. “

                          Chapter 3 – Solar technologies explained

“1) Solar Home System_DC
A solar home system consists of
•        Solar Module ranging from 10 Wp to 60 Wp
•        Battery from 20 Ah to 80 Ah
•        Charge controller 2 Amp to 10 Amp
•        Wiring – DC systems require separate wiring
•        Connected loads – DC lights , Fan, TV etc

All loads/ equipment run directly from the PV/Battery supply and are
designed for 12 V DC operation. The entire system works on DC
power. Hence there is minimal loss. DC energy produced by the solar
panel is consumed by the DC loads. The limitation being the size of the
system and the availability of DC loads/ appliances. Efficient lights and
appliances make best use of the limited supply of electricity. Efficient
DC fluorescent lights are available in 4 to 16 W power rating, in both
tube and compact forms. LED lights are even more efficient, and are
now cheap and reliable.
The solar panels are mounted on the roof with charge controller and
battery kept inside the house. Wiring is done with thicker cables to
interconnect them and to connect them to the loads. Loads located
more than 10 meters away from the battery location need to be avoided.
Small DC home systems are used world wide
•        In houses without electricity,
•        Where power outages are more as a back up,
•         At smaller shops,
•        In some cases replaces kerosene lamp,
•        Schools to rural area
•        Administrative offices located remotely

A solar oven or solar cooker is a device which uses sunlight as its
energy source. Solar Cookers are a form of outdoor cooking and are
often used in situations where minimal fuel consumption is important, or
the danger of accidental fires is high. There are a variety of types of
solar cookers: over 65 major designs and hundreds of variations of
them. The basic principles of all solar cookers are:
        Concentrating sunlight: Some device, usually a mirror or some
type of reflective metal, is used to concentrate light and heat from the
sun into a small cooking area, making the energy more concentrated
and therefore more potent.
        Converting light to heat: Any black on the inside of a solar
cooker, as well as certain materials for pots, will improve the
effectiveness of turning light into heat. A black pan will absorb almost
all of the sun's light and turn it into heat, substantially improving the
effectiveness of the cooker. Also, the better a pan conducts heat, the
faster the oven will work.
        Trapping heat: Isolating the air inside the cooker from the air
outside the cooker makes an important difference. Using a clear solid,
like a plastic bag or a glass cover, will allow light to enter, but once the
light is absorbed and converted to heat, a plastic bag or glass cover
will trap the heat inside. This makes it possible to reach similar
temperatures on cold and windy days as on hot days.”

                                        Chapter 4 - Solar Energy products

“Effects of climate change:
The climate change is causing very serious damage to our mother
earth and its effect is manifested through various phenomena including
1)Global Warming
2)Green House Effect
3)Urban smog
4)Urban heat island effect
5)Acid rain
6)Ozone hole
7)Impact on continents
8)Impact on ecosystem
9)Impact on biodiversity
10)Impact on agriculture”

                                                   Chapter 5 - Climate Change

        “Renewable enrgy accounted for approximately half of the
   estimated 208 GW of new electric capacity added globally in
   2011
        Global renewable capacity excluding hydro reached 390 GW in
  2011
        The total investment in renewables during 2011 was a
  staggering USD 257 billion ...............
        Global Solar water heating capacity reached 232GWth in 2011
by adding 50 GWth during the year
        Global Solar PV installed capacity reached 70 GW in 2011”

                        Chapter 6 - Solar Energy – Global Scenario

“Between 1980 and 2009, energy consumption increased by almost
seven times from 85,334 GWh to 596,943 GWh, which corresponds to
an average annual growth rate of approximately 7.1%. The strongest
increase was the consumption by private households, which increased
by almost 14 times since 1980 at an average annual growth rate of
10%. The reason for this increase was the inclusion of several million
new households and corresponding increase in electrical household
appliances such as refrigerators and air conditioners”

                                          Chapter 8 - Solar power in India

“What is the real cost / qty of power we consume? Generation to home
Any power from power plant to home will have these minimum losses
and need to consider the following in assessing what is the right actual
energy consumed to generate 1 unit of energy for our use when fed
through the grid.
Power plant efficiency – 35%
Storage/No load losses – 20%
Transmission & Distribution losses – 35%
Energy efficiency of the load at our home – 70%

Added to this are the upstream recurring inefficiencies for all fossil fuels
in exploration, extraction, transportation, refining etc.

A simple calculation will reveal that for getting a 1 unit of usable energy
for our home about 10 units of primary energy should be consumed at
the power plant. Here the economic, environmental and social negative
impacts get multiplied several times even though our usage is assumed
to be minimal. This is the real cost of power that we use now from the
grid.”

                                              Chapter 10 – Move of the grid

“Efficient energy use, sometimes simply called energy efficiency, is the
goal of efforts to reduce the amount of energy required to provide
products and services. For example, insulating a home allows a
building to use less heating and cooling energy to achieve and
maintain a comfortable temperature. Installing fluorescent lights or
natural skylights reduces the amount of energy required to attain the
same level of illumination compared to using traditional incandescent
light bulbs. Compact fluorescent lights use two-thirds less energy and
may last 6 to 10 times longer than incandescent lights. Improvements in
energy efficiency are most often achieved by adopting a more efficient
technology or production process.”

                                            Chapter 13 - Energy Efficiency

“Advantages
        Biogas replaces kerosene or LPG for cooking and cut CO2
emission
        Biogas cook stoves help reduce the firewood cooking
        Rural household save time since collecting dung and feeding to
  biogas plant takes much less time than collection firewood and
  preparing cooking fire
        Biogas plant with stove helps to cook faster during anytime of
  day and night
        Biogas plant reduces indoor gas pollution
        Help reduce deforestation and thereby related CO2 emission”

                 Chapter 14 – Other Renewable Technologies

“Green building brings together a vast array of practices and
techniques to reduce and ultimately eliminate the impacts of new
buildings on the environment and human health. It often emphasizes
taking advantage of renewable resources,
e.g., using sunlight through passive solar, active solar, and
photovoltaic techniques and using plants and trees through green
roofs, rain gardens, and for reduction of rainwater run-off.”

                                            Chapter 15 – Green Buildings

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