Download Passive Solar Energy

PASSIVE
SOLAR
ENERGY
Description
 Passive Solar Energy is the use of energy from the sun
without the help of photovoltaics.
What it does
 Passive solar energy is used to convert sunlight into
usable heat, cause air-movement for ventilation or
cooling, or store heat for future use. It is commonly
used to help meet a building's energy needs by means
of architectural design, such as special arrangement of
windows, and utilizing materials such as floors that store
heat, or other thermal mass.
Main Concepts
There are three main concepts of passive solar energy.
They are:
 Daylighting
 Passive heating
 Passive Cooling
Daylighting
•
•
•
•
•
•
•
•
•
•
•
Daylight is the use of natural light to supplement and/or
replace artificial lighting.
Daylighting strategies include:
The proper orientation and placement of windows
Use of light wells
Light shafts or tubes
Skylights
Clerestory windows (Window openings in buildings that are
well above ground level and provide sufficient amounts of
daylight.)
Light shelves
Reflective surfaces
Shading
The use of interior glazing to allow light into adjacent
spaces.
An example of Clerestory Windows, and Glazing.
Passive Solar Heating:
•
•
•
•
Passive solar heating happens when sunlight strikes an
object, and in turn, that object absorbs the heat.
It will occur in a building if windows are oriented
correctly. The most powerful (and common) window
orientation is south, but any placement within 30
degrees of due south is still adequate and useful.
For Passive Heating to be most effective, approximately
eight percent of window to floor area is required for
south walls.
Once the heat is inside the building, various techniques
can be adopted to keep, and spread the heat as needed.
Passive Cooling:
 Techniques opposite to passive solar heating are utilized.
Here, buildings are designed to keep solar and air heat
away.
 Internal heating from animate and inanimate objects is
minimized and dissipated in the environment through
ventilation.
 Shading devices (fixed or adjustable) reduce solar radiation.
A building can be shaded by natural vegetation and using
special glazing in windows. External shading devices can
reduce solar gains by up to 90%, while still admitting a
large amount of indirect light.
 External heat gain can also be minimized by good
insulation, reduced window size and by the use of reflective
materials in the walls and roof. During the building design
stage, attention should be paid to cross-ventilation and the
direction of prevailing winds, the source of cooling nighttime
breezes.
Possible Uses
•
•
•
•
•
•
•
•
•
Passive solar energy methods are a very good way to make
use of the clean and inexhaustible energy from the sun.
Passive heating technology is used as the direct or indirect
gain for power consumption.
It is used for:
-Well-planned indoor heating techniques
-Trombe walls
-Space heating
-Water heating
-Thermo siphon (Thermo siphon is a technique that is based
on natural convection methods circulating liquids without
using mechanical pumps.)
-Thermal mass (also known as the thermal capacitance or
heat capacity) which is used to store the heat.
Passive heating systems are also used in more common
household things, such as: solar ovens, solar cookers, solar
chimneys, earth sheltering, etc.
Solar Ovens
 The solar oven works following the principle of
the greenhouse effect: the sun’s short-wave rays
cross the two glass walls without losing
energy. In touching the internal walls of the oven
(which are covered with a non-toxic paint), they
are transformed into heat rays that can no longer
cross the glass walls. This creates an energy trap
that allows us to cook or heat meals.
Trombe Walls
 Trombe walls are sun-facing walls constructed from
either stone, concrete, adobe, or an array of water
tanks. These materials can each function as a thermal
mass, and when combined with insulated glazing on the
outside, and vents running along the perimeter of the
mass, these walls effectively become a solar thermal
collector.
Trombe Wall
with an overhang to
prevent the hot summer sun
from causing extreme heat.
History
1838
Edmund Becquerel observed and published
findings about the nature of materials to
turn light into energy. They were considered
interesting, but were not pursued.
1860 - 1881
Auguste Mouchout was the first man to patent a design for
a motor running on solar energy. He designed a device
that turned solar energy into mechanical steam power and
soon operated the first steam engine.
1883
Charles Fritz turned the sun's rays into electricity.
His solar cell had a conversion rate of only 1-2%.
1904
Henry Willsie recognized the need to store
generated power and built 2 huge plants in
California. He was the first person to successfully
use power at night, after generating it during the
day.
1956
The first commercial solar cell was made
available to the public at a very expensive $300
per watt.
 1970
The Energy Crisis arose, and suddenly it became
important to find an alternative form of energy as
people realized just how reliant we are on nonrenewable, finite resources like coal, oil and gas for
our everyday needs.
 Solar energy history was made as the price of solar
cells dropped dramatically to about $20 per watt.
Today
There is a renewed focus as more and more
people see the advantages of solar energy, as it
becomes more and more affordable.
 Solar electric systems are now used to power
many homes, businesses, cottages, and even
entire villages in Africa.
 We now commonly see solar cells powering
anything from household appliances to cars.
Sustainability
 With an expected lifetime of another five or six billion
years, the sun is virtually a limitless source of clean
energy. The amount of solar energy reaching the Earth's
surface is enough to fulfill total global power
consumption thousands of times over!
How It Works
Passive solar heating makes use of building
components to collect, store, and distribute solar
heat gains to reduce the demand for space heating.
It does not require the use of mechanical equipment
because the heat flow is by natural means
(radiation, convection, and conductance) and the
thermal storage is in the structure itself.
Advantages
Saves Money
 After the initial investment has been recovered, the
energy from the sun is practically free.
 It will save you money on your electricity bill.
 Solar energy does not require any fuel.
 The savings are immediate and for many years to come.
It is Very Environmentally Friendly
 Solar Energy is clean, renewable and sustainable,
helping to protect our environment.
 Solar Energy does not contribute to global warming, acid
rain or smog.
 It actively contributes to the decrease of harmful green
house gas emissions.
 It's easily generated where it is needed.
A Passive Solar Energy System is
Independent
 Solar Energy can be utilized to offset utility-supplied
energy consumption. It not only reduces your electricity
bill, but will also continue to supply your home with
electricity in the event of a power outage.
 A Solar Energy system can operate entirely independent,
not requiring a connection to a power or gas grid at all..
Low Maintenance
 Solar Energy systems are virtually maintenance free and
will last for decades.
 Once installed, there are no recurring costs.
 They operate silently, have no moving parts, do not
release any smells, and do not require you to add any
fuel.
 More solar panels can be added in the future as your
energy needs increase.
Disadvantages
• The initial cost is the main disadvantage of
installing a solar energy system, largely
because of the high cost of the semiconducting materials used in building one.
• The cost of solar energy is also high
compared to non-renewable utility-supplied
electricity. As energy shortages are
becoming more common, solar energy is
becoming more price-competitive.
• Solar panels require quite a large area for
installation to achieve a good level of
efficiency.
Careers
 The primary needs of the passive solar industry are in design and
construction, with a smaller number of career opportunities in
sales and other support personnel.
 As the need for Solar Power increases, a number of jobs
are expected to be created in areas such as sales, public
relations, human resources, and other support business
personnel for solar energy companies.
 People with backgrounds in the following subjects are likely to be
in especially high demand:
 Engineering
 Electrical engineering
 Construction
 Computer science
 Mathematics
 Business
Sources
 http://www.alternative-energy-news.info/passive-solarenergy/
 http://www.builditsolar.com/Projects/SolarHomes/PasSol
EnergyBk/PSEbook.htm
 http://www.alternative-energy-news.info/passive-solarenergy/
 http://www.wbdg.org/resources/psheating.php
 http://www.house-energy.com/Landscape/PassivePlan.htm
 http://www.energysavers.gov/your_home/designing_re
modeling/index.cfm/mytopic=10250
 http://www.builditsolar.com/Projects/SolarHomes/constr
uctionps.htm
 http://www.dasolar.com/solar-energy/passive-solar
 http://www.makeitsolar.com/solar-energyinformation/03-solar-power.htm
 http://greenterrafirma.com/passive_solar.html
 http://www.renewableenergyworld.com/rea/tech/solarpa
ssive
 http://www.ehow.com/facts_5016246_definitionpassive-solar-heating.html
 http://www.allanstime.com/SolarHome/Trombe_Wall/ind
ex.html
 http://www.house-energy.com/Walls/TrombeWalls.html
 http://www.wbdg.org/resources/daylighting.php