The Effect of Glass Insulation on Solar Panel Productivity
Ramya Durvasula, Priyanka Udayakumar, Kathleen Ruan
Takoma Park Middle School 2011 - 12
Abstract
The purpose of this investigation was to find out how the power (in watts) of a solar panel is affected by
the type of glass insulation layered on top of it. The original hypothesis was that if the voltage, current, and
power of a solar panel was tested under ten different types of glass insulation (no glass, flat glass, concave glass
bowls, concave fused glass, convex glass bowls, convex fused glass, a concave glass bowl resting on top of a
convex glass bowl, concave fused glass resting on top of convex fused glass, a convex glass bowl resting on top
of a concave glass bowl, and convex fused glass resting on top of concave fused glass) then the solar panel will
generate the most power when the convex fused glass is layered onto it. In order to measure the productivity of
the solar panel under different types of insulation, a solar panel was laid out in the sun, and the voltage and
current of the solar panel were measured using a voltage and current meter with each type of insulation layered
onto it. Five trials were conducted. The hypothesis was partially supported. The convex fused glass produced
the most power from the solar panel (2.147 watts average). However, the solar panel with no insulation still
performed better (2.346 watts average). The experiment shows that it is counterproductive to insulate a solar
panel with glass, as the glass always reflects more light than it absorbs, reducing the amount of power produced.
Introduction and Review of Literature
There are so many people in the world living
in rural or isolated areas who cannot afford
electricity through the ground. Many of these
people suffer from extreme poverty, and spend all
of their money on food and housing. They do not
have extra money to spend on electricity, and it is
not considered a necessity. However, electricity can
greatly improve their quality of life. With the help
of solar energy, so many more people will be able
to get electricity at more affordable costs. Solar
energy could enable people to cook more easily,
have air conditioning, have light in the evenings,
and work more efficiently with the help of
machinery. The sun is a natural resource that does
not cost anything, and there are many adverse
people who can benefit greatly from it.
This research was conducted to see how
solar energy can be used effectively in rural areas.
By researching ways to increase the efficiency of
solar panels, eventually others may gain access
electricity. Research was conducted about ways of
insulating solar panels in cost-effective ways such
as layers of glass. This can lead to an increased
efficiency conversion rates. If small solar panels are
still able to convert a large amount of energy, then it
would be a good reason for people in both rural and
TPMS Journal of Science
Page 1 of 7
urban areas to use it. Multiple families could
purchase just one solar panel and have enough
electricity to get through the day.
The testable question was “How is the
power produced by a solar panel affected by the
amount and type of glass insulation layered onto
it?” The original hypothesis was that if the voltage,
current, and power of a solar panel was tested under
ten different types of glass insulation (no glass, flat
glass, concave glass bowls, concave fused glass,
convex glass bowls, convex fused glass, a concave
glass bowl resting on top of a convex glass bowl,
concave fused glass resting on top of convex fused
glass, a convex glass bowl resting on top of a
concave glass bowl, and convex fused glass resting
on top of concave fused glass) then the solar panel
will generate the most power when the convex
fused glass is layered onto it.
In order to learn more about the processes
and applications of solar panels, and find out about
the future of solar energy, past and ongoing
experiments relating to photovoltaics and renewable
energy systems were researched.
A man named Charles Landau is currently
working towards finding the best angle for a solar
panel to be positioned. The study is titled
“Optimum Orientation of Solar Panels.” This study
The Effect of Glass Insulation on Solar Panel Productivity
uses current knowledge about the Sun’s efficiency,
pay the electricity bill every month, interest has
the Earth’s rotation, and the Earth’s atmosphere to
turned toward solar photovoltaics to provide
calculate the optimal angles for positioning a solar
electricity in rural communities. Deng Ltd. is a
panel at multiple latitudes and during all of the
company in Accra that has created feasible and
seasons. In the past, scientists thought that the most
efficient solar power systems used in rural areas.
efficient angle for a solar panel would allow the sun
Deng set up a center in collaboration with Kwame
to directly face the solar panel at noon. This angle
Nkrumah University of Science and Technology
“should be equal to your latitude, plus 15 degrees in
(KNUST) in Ghana and Global Sustainable Energy
winter or minus 15 degrees in summer.” However,
Services in Australia to train people in finding more
this does not account for the entire day, but only
efficient and cost effective ways to use solar energy
considers the maximum efficiency at noon.
in rural areas. Their work is contributing to the
Charles Landau’s method, which is based on
improving the photovoltaic systems in rural homes.
the position of the sun throughout the entire day,
The research said that using photovoltaics
has been found to produce 4% more electricity than
instead of kerosene lamps provides better lighting
this more commonly used method. In order to
and keeps the environment healthier as well as
calculate the optimal angle for a solar panel
saved the home owners 20,000 cedi per month
(approximately), “multiply the latitude by 0.89, and
(worth a little more than a euro). Also, women and
add 24 degrees.” This measurement must also be
children in Ghana found that the systems were
adjusted four times a year, in order to allow for the
helpful because they were able to do chores and
maximum amount of energy to be captured
work at night. More than 600 schools have been
throughout the seasons. For example, in the
equipped with PV (photovoltaic) systems, allowing
northern hemisphere, the solar panels will capture
them to have night classes, including adult
more electricity if the solar panels are angled
education.
towards the north. This is because the sun is
The Great Lakes Renewable Energy
relatively lower in the sky and farther north.
Association recently experimented with the
In August 2008, a man named Tom van
efficiency rates of different types of solar panels,
Diessen published a thesis titled “Design of a Solar
and published the results online. They tested three
Home System for rural Cambodia.” He worked with
different types of solar panels – monocrystalline
a company called KamWorks, a Cambodian
cells, polycrystalline cells, and a more recent model,
company who is working towards providing
amorphous cells. They concluded that the
electricity to the 85% of the Cambodian population
monocrystalline cells have a high efficiency rate of
who are currently without power. Tom van Diessen
12% - 16%, polycrystalline cells have a good
was trying to find a simple, easy to set up solar
efficiency rate of 11% to 13%, and amorphous cells
home system that could provide electricity to the
have a low efficiency rate of 8% - 10%. However,
population without requiring an electric grid. He
amorphous cells are much cheaper to manufacture
designed a foldable solar home system. It is created
than monocrystalline cells, so it may be more costso that the solar panel can be easily extended up to
effective to use amorphous solar cells.
14 feet into the air from a base, using a flexible
In 2005, Michael Gratzel, Laboratory for
pole. The panel can then be adjusted very easily in
Photonics and Interfaces, Swiss Federal Institute of
order to maximize efficiency during the four
Technology, did an experiment to determine the
seasons. This research is very helpful, as it shows
efficiency of dye-sensitized photovoltaic cells. The
how to work towards creating a simple design that
results of this experiment were published in an
can benefit people in rural areas.
article titled “Solar Energy Conversion by dyeAn article written by anonymous titled
sensitized photovoltaic cells.” Dr. Graztel believes
“Solar power for rural communities” explains how
that humans will eventually run out of energy if we
Deng ltd, a company working on improving solar
do not start using solar energy, and that this is
photovoltaics, has created a centre in Ghana to
necessary progress. Solar energy is relatively cheap
improve the solar energy systems in Ghana. Since
after some point, and it is easily accessible, which is
the chance of rural areas connecting to national
something Dr. Graztel hopes to make use of.
electric grid is very remote and even if that did
In this experiment, the scientists from the
happen many families would not be able to afford to
Swiss Federal Institute of Technology tested the
TPMS Journal of Science
Page 2 of 7 The Effect of Glass Insulation on Solar Panel Productivity
efficiency of converting energy from the sun to
electricity. They used dyes to sense the light passing
through it. When the electrons pass through the film
membrane of the solar panel and into the collector
electrode, the electricity is collected. By measuring
the amount of energy going into the electrons and
how much energy is produced after passing through
the solar panel, they were able to conclude that over
11% of the energy is actually converted into usable
electricity using the solar panels. Although this is a
lot of electricity, it would still be more costeffective and energy-efficient to increase this
percentage. This research shows that dye-sensitized
cells are efficient, although they may not be as
efficient as other types of solar cells.
The original hypothesis was based on the
idea that the convex glass would absorb light and
cause it to bounce around within the solar panel,
while also reflecting the least amount of light.
However, the dessert bowls were textured, so they
contained air bubbles. This would reduce the
absorption rate, therefore decreasing the amount of
power generated by the dessert bowls throughout all
of the experimental trials.
Materials and Methods
The materials needed for this experiment
include one solar panel, two clear, slumped, 6 inch
x 6 inch glass sheets, two clear glass dessert bowls,
one 6 inch x 6 inch sheet of flat glass, and one
voltage and current meter.
First, the solar panel was set up in an open
area on a sunny day. Then, the amount of voltage
and current produced by the solar panel without any
glass on it was measured using the voltage and
current meter.
Then, this step was repeated, testing the
solar panel with one flat sheet of glass, one concave
curved sheet of glass, one concave curved glass
bowl, one convex curved sheet of glass, one convex
curved glass bowl, 2 curved closed glass sheets, 2
curved closed glass bowls, 2 curved open glass
sheets and 2 curved open glass bowls.
The amount of power collected by the solar
panel for each independent variable was calculated
by using the equation “Watts = Volts * Amperes.”
Lastly, each step was repeated four times in
order to have five trials per insulation method.
Results
In the study of the effect of insulation on the
amount of power output by a solar panel, curved
and flat sheets of glass and glass bowls were placed
on solar panels to test how the amount of power
output was affected. The control variable, the solar
panel without a piece of glass, output 2.34633206
watts of power. The panel with the curved convex
glass sheet had an average power output of
2.1466392 watts which was the second greatest
source of power and the glass bowl when placed
upside down had an average of 2.1019776 watts.
The concave piece of glass and the concave glass
bowl both had lower averages of 1.29429512 and
1.9162202 watts, respectively. The panel with the
flat piece of glass had a fairly high power output of
2.08231416 watts. The panel with the stacked
curved closed glass had a power output of
1.62020812 watts and the panel with the stacked
curved closed bowls output 1.48096224 watts.
Lastly, the panel with stacked curved open glass
sheets had an output of 1.69899008 watts and the
panel with stacked curved open glass bowls had an
output of 1.54150176 watts. The control variable
output about .19969286 watts more than the panel
with the second best type of glass insulation, the
curved convex glass sheet. For the majority of the
trials, the curved bowls performed worse than the
curved glass sheets. In general, the stacked glass
bowls and sheets had a worse effect on the power
output by the solar panels. The control variable, the
solar panel without a piece of glass, had the greatest
amount of average output power. The data shows
that the control performed the best which means
that the insulation from the glass does not improve
the power output of the solar panels through this
experiment.
Insulation Type
Control
Curved Convex n (glass)
Curved Convex n (bowls)
Flat
Curved Concave U (bowls)
Curved Open >< (glass)
Curved Closed O (glass)
Curved Open >< (bowls)
Curved Closed O (bowls)
Curved Concave U (glass)
Average Wattage (Watts)
2.346
2.147
2.102
2.082
1.916
1.699
1.620
1.542
1.481
1.294
Table 1: The effect of insulation on power produced
TPMS Journal of Science
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The Effect of Glass Insulation on Solar Panel Productivity
Discussion and Analysis
The purpose of this investigation was to find
out how the power (in watts) of a solar panel is
affected by the type of glass insulation layered on
top of it. The original hypothesis was that if the
voltage, current, and power of a solar panel was
tested under ten different types of glass insulation
(no glass, flat glass, concave glass bowls, concave
fused glass, convex glass bowls, convex fused glass,
a concave glass bowl resting on top of a convex
glass bowl, concave fused glass resting on top of
convex fused glass, a convex glass bowl resting on
top of a concave glass bowl, and convex fused glass
resting on top of concave fused glass) then the solar
panel will generate the power when the convex
Graph 1: The effect of insulation on average power
fused glass is layered onto it. The glass bowl refers
(Watts) produced by a solar panel.
to a 2 mm thick, textured dessert bowl, while the
fused glass refers to 4 mm thick, fused, slumped
Bull’s-eye glass.
The results obtained in the experiment
partially support the original hypothesis. The
convex fused glass performed the best out of all of
the experimental trials, with an average power of
2.147 watts. The convex dessert bowl had a similar
performance rate, with an average power of 2.102
watts.
The original hypothesis was based on the
idea that the convex glass would absorb light and
cause it to bounce around within the solar panel,
while also reflecting the least amount of light.
However, the dessert bowls were textured, so they
Graph 2: The effect of insulation on average voltage
contained air bubbles. This would reduce the
(Volts) produced by a solar panel.
absorption rate, therefore decreasing the amount of
power generated by the dessert bowls throughout all
of the experimental trials.
A pattern that was seen among the
experimental trials was that as the ratio of internal
surface area of the glass to external surface area of
the glass increased, the amount of power generated
decreases. The flat glass, for example, had the same
internal surface area as external surface area, so it
had a higher ratio than that of the convex glass. It
also had a lower average power, 2.082 watts. The
concave glass had the highest ratio, and the lowest
average power, 1.294 watts.
Although the data supported the portion of
the hypothesis that stated that the convex fused
glass would outperform all of the other
Graph 3: The effect of insulation on average current
experimental trials, the control trial still did better.
(Amperes) produced by a solar panel.
In fact, our data showed that layering glass on top
of the solar panel always decreases the amount of
TPMS Journal of Science
Page 4 of 7 The Effect of Glass Insulation on Solar Panel Productivity
power produced. The control panel with no glass on
it had the highest average amount of power, 2.346
watts, in comparison to the 2.147 watts generated
by the convex fused glass. Therefore, it is
counterproductive to insulate a solar panel with
glass, as the glass always reflects more light than it
absorbs, reducing the amount of power produced.
During experimentation, we planned to use a
different solar panel for each trial. However, we
found that without any insulation, some solar panels
generated more power than others. Also, it was
impossible to have all of the solar panels in the
exact same position. We solved these problems by
using only one solar panel to test all of the
experimental glass insulation. Although this solved
the first two problems, it led to another problem.
There was a slight change in time between our first
experimental trial and our last experimental trial,
due to the fact that we could not have all of the
trials running at once. As the time changed, the
weather conditions were guaranteed to change
slightly as well, which could lead to inaccurate
measuring.
In order to improve the experiment, solar
panels should be tested in different weather
conditions and times, rather than conducting all of
the trials on one day. Also, using multiple
measuring instruments or a more precise measuring
instrument may improve the validity of the data. To
further investigate the principles tested by this
experiment, it may be beneficial to experiment on
the effect of different types of window glass on the
absorption rates of windows, the effect of
temperature on the efficiency of solar panels, and
the effect of the angle and direction of a solar panel
on its efficiency rates.
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