Make electrons sweat
At the same time you see graphs that show how much electricity the sun makes,
you will also see graphs that display the amount of electricity that is required
to run the entire school. The 2,000-watt solar energy system won't power
the school by itself. AEP generates the rest of the energy the school needs
from coal, nuclear energy, natural gas and hydropower. AEP tries to generate
and deliver electricity as wisely as possible, squeezing all the electrons
we can from our natural resources, stretching out the supply of fossil fuels,
reducing our effect on the environment and saving money so you pay less for
electricity.
You're already doing the
easy stuff to save electricity,
like turning off the lights
when you leave the room, but
how about when you're using
electricity? Are you making
those electrons work as hard
as you can?
Are they sweating?
You can make electrons work harder — really make them sweat — by
trying to use the same stuff you already do but with less electricity. By being
more efficient with electricity, less fossil fuel needs to be burned, so fewer
emissions are released into the environment. Take lightbulbs, for example.
Everyone needs to light up areas of their house or school to see. But instead
of using the same kind of lightbulb everywhere, you can choose the bulb that
makes just the right amount of light to read, so you don't over-light your
reading area. That's making electrons work hard. If you can use fluorescent
bulbs, they are even more efficient than incandescent ones because they produce
the same amount of light with less electricity.
At
AEP, we've done the same thing.
First, we looked at how we
lighted our 12 million square
feet of building space. Then,
using tips from USEPA, we figured
out that by changing the bulbs
or the fixtures for them in
about six million of those
square feet, we could save
23 million kilowatt-hours of
electricity each year. So,
over a five-year period, we
did change those bulbs and
fixtures. Now, we're saving
a lot more than electricity.
It takes about a pound of coal
to make one kilowatt-hour,
so we're saving a lot of coal,
too. Also, we reduced our yearly
gas emissions of sulfur dioxide
by 377 tons, nitrogen oxide
by 144 tons and carbon dioxide
gases by 29,295 tons. In fact,
the USEPA thought AEP did a
pretty good job of living up
to our Green Lights Program
pledge to be more efficient
and help our customers do the
same, so it gave us the Utility
Ally of the Year Award.
Another way you can make
electrons sweat is to use geothermal
energy to heat and cool your
house. Water in the ground
is warm, and it has energy
in it that can be taken out
with a heat pump. The U.S. EPA
says that using a geothermal
pump is the most efficient
way to heat and cool your house.
AEP is helping customers learn
about geothermal systems so
they can use more of them.
AEP has been burning coal
for a long time and has learned
how to get the most electricity
it can from its power plants.
Whenever you convert one form
of energy into another, you
lose some usable energy. As
we take the energy out of coal,
for example, we lose about
65% of that energy. That means
we're about 35% efficient,
which is better than the average
for all U.S. coal-burning power
plants. BUT, we also have figured
out how to burn coal even more
efficiently -- around 50% more
efficiently. It's a really
different way that requires
a whole new power plant. We
tried out this new way in a
small, old power plant in Ohio.
When we build our big, new
plants for this clean coal
technology, their designs will
be based on what we learned
at the experimental plant.
Using electrotechnologies
can boost efficiency, save
electricity and help the environment.
You don't know what electrotechnologies
are? Well, they're all around
you. One of the first electrotechnologies
was the refrigerator. People
used to use big blocks of ice
in a box (hence the name "icebox"),
but the refrigerator quickly
became a big hit. Same with
vacuum cleaners (people used
to hang rugs on a clothesline
and whack them to get the dirt
out). Your computer is another
example of electrotechnology,
especially when you send e-mail
or a fax instead of mailing
a letter. Industry uses electrotechnologies
all the time.
When the sun hits the solar
panels at Bluffsview and everything
is perfect, 85% of the
sun's energy is lost because
the silica crystal cells are
only 15% efficient converting
sunlight into electricity.
What can make the solar cells
less efficient? If it is cloudy,
trees or the building shade
them, if they have dust or
snow on them. Sunlight will
reach the solar cells through
snow, but not as much. By the
way, remember the light bulbs?
It's the same with solar cells
and bulbs. You need to dust
off your bulbs so all the light
they make gets into the room.
If the solar cells aren't
oriented to receive the sun's
rays head on, they won't make
as much electricity. BP Solar
used a computer to find out
the best orientation by compass
direction and tilt angle to
the sun. The best compass angle
is true south. It turns out
that you could make a big mistake
and line up the cells way off
true south and the solar cells
would still be pretty efficient.
But If you didn't have the
tilt angle just right, the
cells wouldn't make nearly
the electricity they could.
What's so important about
the tilt? It's because the
sun is higher in the sky in
the summer and lower in the
winter. At the Bluffsview School,
that's a 40 degree range, which
is a lot. If Bluffsview kids
wanted to really make the electrons
in the solar cells work hard,
they'd change the tilt angle
every month, according to BP
Solar's computer results.
If no one wanted to change
the tilt, BP Solar says the
tilt can be 40 degrees all
the time for average efficiency.
The 40 degree tilt is the same
as the latitude for the school.
You can see why BP Solar gave
the best angles for the Bluffsview
Project. The sun's angle is
pretty important to know so
that the tilt angle of the
solar panels can be set for
the highest efficiency. You
can also figure out the sun's
angles for your school or anywhere
else using the SUNANGLE program
found on http://susdesign.com/sunangle/.
Putting the Sun in a Tube
Sometimes by looking at things in a different way, you can do it better.
Yu
Kun Pei (or Y.K. for short)
was working at Owens-Illinois
Inc. in Toledo, Ohio, not far
from Bluffsview School, when
he was asked to make something
that could collect solar energy
better than anything else.
Y.K. thought that if he could
do that, he could help Chinese
families heat up water for
tea and taking baths instead
of cutting down trees and burning
them to make hot water. In
many places in the People's
Republic of China, people don't
have natural gas or electricity
to make hot water like we do
in the United States. But Y.K.
lives by the saying, "Do not
reach for the sky without your
feet planted firmly on the
earth." He said, "If we cannot
make the collector for the
sun's energy affordable and
safe, then it doesn't really
matter how good it is." He
knew that if people didn't
have enough money to buy his
invention, they'd keep using
firewood.
Y.K. spent some time thinking
about this challenge. He knew
all about glass since he'd
been working with it for about
45 years. He'd studied how
the sun's rays were used by
collector boxes made of flat
plates of glass to capture
energy. Instead of converting
the sun's rays into electricity
like the solar cells at Bluffsview,
the boxes used rays to heat
air or liquids inside the box.
Then the energy in the air
or liquid was used to heat
water for cooking, washing
clothes or bathing, or to heat
the air in homes.
Ever entered a car on a hot
summer day? You already have
an idea of how hot it can get
inside the collector box.
Finally, the idea came to
him. He decided to roll the
flat plate of glass into a
tube, put one tube inside another,
and paint the insides of the
tubes black and silver, to
bring as much of the sun's
energy inside the tubes and
keep it there. He also took
out the air between the two
tubes and sealed the ends of
the tubes to create a vacuum
to really lock in the energy.
Here's a sketch of his collector
tube. (Refer to Diagram
1) The tube is 2 inches
in diameter and 44 inches long.
Y.K. laid them next to each
other pointing south so they
could catch direct beams of
light from almost any point
in the sky as the sun moved
overhead. The tubes also catch
reflected (diffuse) light from
all sides (Refer to Diagram
2) Y.K. put a thermometer
inside the hollow tube on a
sunny day and discovered he
had truly captured the sun
in the tube when he measured
575 degrees Fahrenheit!
By putting the tubes end-to-end
and plugging the outside ends,
he could direct the hot air
out of the tubes to heat water
in a tube or tank. (Refer to Diagram
3) Now that he had invented
tubes that worked, he had to
find out if his tubes were
better than flat plate collectors.
So he compared the two by taking
different measurements. First,
he measured how much energy
could be collected by each
and found out that the tubes
collected more than the flat
plate for a longer time throughout
the day (Refer to Diagram
4) "This is good," he
said.
Then he measured the efficiency
of the tube and the flat plate
collectors when it was cold
(20 degrees F.) and hot (80
degrees F.) outside and discovered
that the tube was more efficient
than the flat plate and that
the tube worked at the same
efficiency whether the temperature
was 20 or 80. (Refer to Diagram
5) "This is very good," he
said.
Finally, he made temperature
measurements as it got warmer
and cooler outside and inside
the tube and flat plate collectors
and monitored solar radiation
as it changed throughout the
day. He calculated the percent
efficiency of the collectors
and found that his tube was
more efficient than the flat
plate all day. (Refer to Diagram
6) "This is GREAT!" he
said.
Remembering to keep his feet
firmly on the ground, he started
CONSOL Energy Co. and is making
many of tubes at a time to
keep the cost of each tube
low so everyone will be able
to buy them. Oh, yes, even
though they are made of glass,
they don't break very easily
so they are safe.
If you would like to watch
a video on YK Pei's accomplishments,
just click on the video link
below!
Video
on Y.K. Pei (Real Media:
5:21, 20KB/sec: get
viewer)
Want to ask Y.K. questions
about his sun capturing tubes?
You can send an e-mail to
Y.K. in China in care of his
son, Gee Pei, at: gpei@netvigator.com.
Y.K. and his son will be
happy to hear from you.
Fuel cell electrical efficiency
Still another way to make electrons sweat is to use something called a fuel
cell to change the energy in hydrogen into electricity. Fuel cells can be
very efficient at making electricity, and researchers are looking for ways
to make the electrons from them sweat even more. To learn more about fuel
cells, check out 'Fuel
cells – another way to generate electricity.'
