Transcript STEM An Arctic Solar Shelter Design Challenge Integrating the Engineering Design Process into a study of the Arctic Region.

STEM
An Arctic Solar Shelter
Design Challenge
Integrating the
Engineering Design Process
into a study of the Arctic Region
Kotzebue, Alaska is located 33 miles
north of the Arctic Circle
You can learn more about Kotzebue
by visiting their web site.
http://kotzpdweb.tripod.com/city/index.html
An Aerial View Of Kotzebue
http://en.wikipedia.org/wiki/Kotzebue,_Alaska
Students in that community attend
the Kotzebue Middle/High School
Visit the school’s web site at:
http://www.nwarctic.org/Schools/kmhs/index.htm
20 days of sunlight
Because Kotzebue is just north of the
Arctic Circle, there are 20 days each year
when there are 24 hours of daylight.
The summer solstice is in the middle of that
20 day period.
Would it be possible to take advantage of
that 24 hours of sunlight to heat a shelter for
Arctic researchers?
The Arctic Solar Challenge
Design, build, and evaluate
the performance of a portable,
temporary, passive solar
structure that can be used as a
shelter for researchers who will
be in Kotzebue, Alaska around
the time of a summer solstice.
.
In the Arctic Region, there is an interesting
“window of opportunity” for a passive solar collector
in terms the number of hours of daytime.
http://www.eoearth.org/article/Earth-Sun_relationships_and_insolation
There is also a window of opportunity in
terms of solar insolation.
http://www.eoearth.org/article/Earth-Sun_relationships_and_insolation
Materials you can use to build a
model of a solar shelter include:
•
•
•
•
•
•
•
A photocopier paper box
Transparent window material
Reflective Foil
Paper of different colors
Scissors
Insulating Materials
Other Easily Obtained Materials
The Engineering Design Cycle is one way to describe
the process of designing, building, and evaluating the
performance of a model of an Arctic solar shelter.
Page 84 of the Massachusetts Science and Technology/Engineering Framework
Designing and building a passive solar shelter
provides an opportunity to evaluate how
energy is transmitted and transformed.
• Visible light and near infrared energy
radiates from the sun and passes though
windows of a passive solar collector and can
be transformed into heat (thermal energy).
• Heat is conducted through the walls of a
structure from a warmer environment to a
colder environment.
• Convection currents will form as air inside a
building expands and rises as it is heated or
compresses and sinks as it cools.
The angle of incidence of radiated sunlight entering
a window changes as the seasons change and also
depends on Latitude. The angle of incidence is also
called the “altitude” of the sun.
http://www.azsolarcenter.com/design/pas-2.html
You can design the location of windows so that
the maximum amount of sunlight enters the
structure and is converted into heat.
.
Insulating materials selected for your model of a
shelter will reduce the loss of heat by conduction. The
value of those materials depend on
The thickness of the insulating material
The type of insulating material
Strategies used to insulate windows when there is
little or no solar gain
T2
T1
http://sol.sci.uop.edu/~jfalward/heattransfer/heattransfer.html
Even igloos have insulated walls.
Air spaces in the blocks of snow reduce
the reduce the rate at which energy is
conducted though the walls.
http://en.wikipedia.org/wiki/Igloo
You also need to manage the flow of air into
and out of your model of a polar solar shelter.
http://www.azsolarcenter.com/technology/pas-3.html
Some igloos are built to manage convection!
Entryways of many igloos are designed to be
lower that the elevated sleeping area.
http://en.wikipedia.org/wiki/Igloo
Design a Valid Test.
You need to simulate the conditions
that polar researchers experience in
Kotzebue, Alaska when you collect
data with your model of a Arctic solar
collector.
For today’s weather in Kotzebue visit:
http://www.wunderground.com/US/AK/Kotzebue.html
The angle of incidence of sunlight
is one factor to consider when
designing a fair test of your Arctic
solar collector.
The maximum angle of incidence
of sunlight entering your passive
solar collector needs to be similar
to the maximum angle of incidence
of sunlight in Kotzebue.
The midday sun in Kotzebue
The highest altitude of the sun in Kotzebue on the
first day of summer is 46.5º.
The U.S. Naval Observatory web site provides
the sun’s altitude data for any location.
.
http://aa.usno.navy.mil/data/docs/AltAz.php
The midday altitude of the sun is also
approximately 46º F on the following
dates at the following locations.
• In Corpus Christie, TX on February 5th
• In Charlotte, NC and Flagstaff, AZ on
February 27th
• In Columbia, MO on March 7th
• In New York City and Redding, CA on March
12th
• In Detroit, MI and Boston, MA on March 17th
These dates would occur during a time
periods when a test of a design of a polar
solar shelter could be conducted.
.
Average daily temperatures are also an
important factor when evaluating the
performance of a model Arctic solar shelter.
Between the summer solstice and the
middle of August, average high temperatures
in Kotzebue range from 50º F to 60º F. The
daily low temperatures range from 30º F to
50º F.
A NOAA web site can be used to compare early
summer temperatures in Kotzebue with
other locations at other times of the year.
http://www.cdc.noaa.gov/USclimate/states.fast.html
This web site provides an animation that can
be used to evaluate how the “sunshine factor”
affects the window of opportunity for using
a passive solar collector in the Arctic Region.
http://www.fao.org/WAICENT/FAOINFO/SUSTDEV/EIdirect/climate/EIsp0002.htm
Other factors to consider when
determining the fairness of the test
of the performance of a model of an
Arctic solar shelter include:
•
•
•
•
Topography
Wind direction and speed
Ground temperature
Any other factors?
A series of tests of the performance of a model of an
Arctic solar shelter also provides an opportunity to
evaluate relationships among scientific variables.
• Controlled variables remain constant from one trial
to the next. Examples include the angle of incidence
of sunlight and outside temperatures.
• An independent variable changes from one trial to
the next. An example would be the thickness of
insulation in the floor, walls, and roof.
• A dependent variable is one that depends on a value
of an independent variable. An example would be
changes in the shelter’s temperature that results
from a change in the thickness of insulation.
Lower Latitude applications of designing
a passive solar Arctic shelter include:
• Describing how your design can be
adapted for use in your region in either
cooling or heating seasons.
• Determining the passive solar potential
of your school building.
• Evaluating the ecological advantages
of passive solar structures.