Note: Descriptions are shown in the official language in which they were submitted.
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Description
Several renewable and non-renewable energy sources are available to match
specificity of local
energy needs. Abundance of free solar energy has spurred technology and
commercial
developments for innovative solutions to address specific energy and heat
requirements. The
success of feed-in-tariff programs helped the photovoltaic power generation to
become a major
contributor to the overall energy mix. The development of large-scale
manufacturing and
efficient logistics has helped the reduction of the capital cost of solar
modules and other balance-
of-system components. The focus on the integration of theses solar modules
into standardized
grid-connected power generator has reduced the interest into innovative energy
solutions that
could address important challenges within a sustainable scheme. For example,
instead of
upgrading grid to accommodate increasing intermittent renewables, development
of appropriate
integrated solar power generation for local consumption is a better option in
some cases.
Solar powered lighting system may provide a sustainable solution to increasing
electricity
demand. In some areas with high solar radiation, excess electricity production
could be even
used for other applications particularly during peak load hours. Often this
peak load occurs
during daytime when outdoor lighting is not required.
Lighting represents more than 20% of the overall electricity in developed
countries. Street
lighting contribute significantly to this overall electricity demand. High
installed cost of solar
powered lighting systems is a significant hurdle. This is particularly the
case for remote areas
with no electric grid and/or expensive electricity sources. Maintenance of
these lighting systems
is also expensive for local communities. For some municipalities, it's the
most important budget
item.
Several patents have been published in the area of solar lighting. US patent
4,200,904 filed in
1978 describes a standalone solar powered street lighting system including a
maintenance-free
battery with sufficient storage capacity to power street lights and/or traffic
signals. Additional
auxiliary generator could be needed to provide energy when sufficient sunlight
is not available
for an extended period of time.
US patent 6,120,165 filed in 1998 describes a solar powered outdoor lamp with
a stand
supporting a solar module. Incandescent lamp and a halogen lamp are also
included along with
CA 02901475 2015-08-25
passive infrared motion detector. The halogen is used for intruder detection
in security
applications.
US patent 7,832,892 B2 filed in 2008 describes a two LED lamps solar powered
lighting
assembly. Each LED lamp includes a photovoltaic panel installed on the top of
the
lamp frame.
Previously mentioned patents are mostly based on standard photovoltaic module
mounted on top
of a post. These designs provide electricity output to low lighting
requirements. Large solar panel
up to around 10 m2 may be required to satisfy electric power requirements for
high flux lighting
system. High surface area solar panel may raise issues related to mechanical
stability and cost of
integration. This is particularly the case in highways and remote places where
high intensity
lighting systems are required. Higher surface area is needed even in areas of
high solar
radiations. Furthermore, design of the solar lighting should provide high
surface area and high
solar-to-electricity conversion efficiency. To avoid additional capital and
operation costs, we
need to use simple and standard fabrication and integration processes. For
example, using solar
cells or solar modules produced by custom-made manufacturing processes and
machinery
increases the overall cost.
The surface area of the pole may provide large area for integrating large
numbers of solar panels.
For example, with a square base pole having 25 cm each side and 10 m high,
available surface
area for integrating solar cells or solar modules is estimated at 10 m2.
Potentially this could
provide around 1000 W installed electric power capacity. However, the
efficiency of solar
collection will be reduced because of potential shading and non-tilted solar
panel. Furthermore
all the faces do not have the optimal azimuthal angle. Solar panel with
standard length will be
used. For example, solar module around 120 cm long is suitable. Solar panels
containing one raw
of solar cells could be obtained using conventional back-end manufacturing
processes and
machinery. Modules with different size could be also used depending on the
power requirements
and the geometrical dimensions of the lighting pole.
US patent 2014/0041714 Al describes a tubular solar system laminate for
integration into solar
lighting system. Requirement for flexible solar cell and tubular high quality
glass makes this
solution very expensive. Furthermore, around 50% of solar cell will not be
exposed to direct
solar radiation. Furthermore, the vertical position of the solar module will
reduce significantly
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the solar radiation collection efficiency. This design will make the overall
energy efficiency of
the system even lower.
We propose solar lighting pole with triangular, square or trapezoidal,
octagonal or hexagonal
cross-section base to provide maximum surface area exposed to direct solar
radiation. Other non-
circular cross-section shapes could be also used. Depending on the cross-
section, the pole will
provide 3, 4, 5 or 6 faces to accommodate solar panels. Lighting poles having
different cross-
section shapes could be also used depending on the application and local
requirements. For
example, these different shapes may provide architectural and design
flexibility. Local
requirements may dictate the choice. These requirements may include installed
capacity,
mechanical and style needs.
Properly designed solar panel placed on the different faces of the pole will
allow production of
electricity of sufficient amount even in low solar radiation sites. South-east
and south-west
facing panels will have a reduction of electricity output of around 10% when
compared to true
south rated power. However, the multitude faces with different azimuthal
angles will give raise
to high power capacity during longer hours of the day. This will allow
utilisation of the excess
solar power in peak load management. This is particularly the case when the
battery is 100%
charged.
Figure 1 shows a schematic representation of a 10 m height solar powered
lighting pole. This
pole could be made of a single unit or multiple sub-units. Each pole face may
contain at least 5
inclined photovoltaic solar panels around 120 cm long. Longer or shorter solar
modules could be
also used. This will affect the overall number of modules per lighting pole.
Depending on the
pole cross-section dimensions, at least one row of solar cells could fit on
each pole face. Solar
panel tilt orientation will help optimize solar-to-electricity conversion.
Additional components of
the lighting system include battery storage, motion sensor and charge
controller.
The pole should be oriented properly by different means before permanently
fixed to the ground.
Note shown in Figure 1, is the possibility to rotate de pole before permanent
fixing. An angular
adjusting ring at the pole base allows optimization of the azimuthal angle.
This will help
optimize further the solar-to-electricity conversion efficiency.
Both crystalline silicon and thin-film based solar modules are suitable. Thin
film based solar
modules may provide an advantage in some specific applications. For example,
in additional to
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using an optimal tilt and azimuthal angle for the solar panel, CulnõGiSySei -y
could provide help
reduce glare. This option could be for example used in highway and near
metropolitan areas. In
addition to this, solar panels are attached around 2.70 m or higher. In some
cases the clearance
height could be even bigger. The final clearance height could be dictated by
other local
requirements. The pole height and the number of solar modules will be adjusted
accordingly.
Figure 2 provide a schematic representation how the bottom and top of each
photovoltaic panel
are fixed to a single metallic piece. This metallic piece is fixed to the pole
before solar module
integration. This reduces time and cost of solar module installation.
Different means could be
used to fix the metallic piece to the lighting pole. Preferable position of
holes with appropriate
sizes are shown in Figure 2. This facilitates fixing the metallic piece to the
pole. Dimensions of
this piece are provided in cm units. Additional mean could be added to provide
mechanical
stability for the solar module. For example, one or more screws could be used
to attach the solar
module and the metallic piece together.
Figure 3 provides a horizontal cross-section of the pole including the solar
panel in the case of
trapezoidal shape. The regular trapezoidal cross-section provides one face,
around 34 cm and up
to 10m long, for display or other applications. The other three faces are used
in this example as
support of solar panels. These three faces are 21 cm wide.
The metallic piece is not shown in Figure 3. This piece could be fixed against
one or multiples
faces of the poles. Fixing against multiple faces of the poles could provide
additional stability.
Three holes to help installer fixing the metallic piece, before module
integration, are shown.
Each hole is positioned at the center of each face.
