• Solar Energy reaching the earth is incredible. By
one calculation, 30 days of sunshine striking the
Earth have the energy equivalent of the total of all
the planet’s fossil fuels, both used and unused!
• All chemical and radioactive polluting byproducts
of the thermonuclear reactions remain behind on
the sun, while only pure radiant energy reaches the
• The surface receives about 47% of the total solar
energy that reaches the Earth.
Active Solar : A method specifically designed to acquire
energy from sun and move it to where needed, including:
o Photovoltaic electric power generation o Solar
Thermal power generation o Active solar heating using
Passive Solar : A design of buildings that inherently
takes advantage of the sun for day lighting and winter
heating, and avoids solar gain in summer to minimize
need for cooling. A good example of contemporary
passive solar architecture are Auroville.
CATEGORIES OF SOLAR ENEGRY :
• The word ‘building orientation’ is basically the positioning of a building with
respect to the sun, usually done to maximize solar gain at the appropriate time of
the year when required in a cold climate and to minimize solar gain in a hot
• East and west receive maximum solar radiation during summer. West is a crucial
orientation because high intensity of solar radiation is received during evening
hours, when the internal gains are also at its peak.
• Deep verandahs or sunshades in the south and west facades would effectively
exclude these strong evening rays.
• The most frequently used rooms during the day are oriented in the East and the
North whereas the rooms that are used mostly at night are restricted to the South
and the West, which are hotter directions.
•While deciding the building orientation, one must also take into consideration the
location of landscape features in a plot, i.e. trees, planters, etc. which will affect the
building depending on sun direction and sun path.
• In passive solar building design, windows, walls, and floors are
made to collect, store, reflect, and distribute solar energy in the
form of heat in the winter and reject solar heat in the summer.
This is called passive solar design because, unlike active solar
heating systems, it does not involve the use of mechanical and
• Passive solar design refers to the use of the sun’s energy for the
heating and cooling of living spaces by exposure to the sun.
• When sunlight strikes a building, the building materials can
reflect, transmit, or absorb the solar radiation.
• The heat produced by the sun causes air movement that can be
predictable in designed spaces.
• Passive solar cooling systems include overhangs or
shades on south facing windows, shade trees, thermal
mass and cross ventilation.
PASSIVE DESIGN STRATEGIES :
•Building organization and spatial layout
•Size of openings
•Volumes of spaces
SOLAR PASSIVE TECHNIQUES :
SOLAR PASSIVE TECHNIQUES
PASSIVE COOLING PASSIVE HEATING
DIRECT GAIN INDIRECT GAIN
ROOF SPACE COLLECTOR
THERMAL STORAGE WALL SYSTEM
VENTILATION & OPERABLE WINDOWS
EARTH AIR TUNNEL
ROOF POND SYSTEM
Active Solar Heating System :
Solar collector collects the energy and distributes it to
interior system via air or fluid.It’s economical when the
It reduces greenhouse gases and air pollution since it uses
Photovoltaic (PV) Systems :
This system uses photovoltaic process. Radiation energy
captured by solar cells in terms of photons is used to
Pros: Easily extandible, transportable, no pollution.
Cons: High cost for establishment.
•Renewable, Abundant, Sustainable:
Renewable: Solar energy will never be run out of itself due to estimations.
Abundant: The surface of the earth gets 120,000 terawatts of solar radiation
(sunlight) – 20,000 times more power than what is needed to supply the whole
Sustainable: Solar energy can never be over consumed.
• Environmentally Friendliness & Good Availability:
Environmentally Friendly: It doesn’t cause any pollution in general.
Good Availability: Sun is everywhere.
•Reduces Electricity Cost:
By using solar energy, electricity bills lowers due to usage of less power in the
There is no moving part while using solar energy. All system is silent, meaning
that it is suitable for general usage.
PROS OF SOLAR ENERGY :
At first sight, some money needs to be invested during manufacturing. Also, if
it is wanted to be used later, it needs to be stored and energy storage requires
Solar energy is available only if there is sun. If the user want to use it at night,
it needs to be stored which is quite expensive.
• Exotic Materials:
During manufacturing, some materials are needed which are rare in nature and
they are quite expensive. Copper indium gallium selenide (CIGS) is used for
• Associated with Pollution:
Some manufacturing process of solar energy causes greenhouse emissions.
Transportation of materials also causes pollution. The impact of these gases is
on global warming compared to carbon dioxide is about 1000 times greater.
• Requires Space:
Power density, or watt per square meter (W/m²), is calculated when the
manufacturers calculate how much power can be derived from the system. If
the density is low, it is better; so solar energy installation requires space.
CONS OF SOLAR ENERGY :