A.P. Environmental Science
Passive Solar Design Project
Assignment: Working alone or with a partner, design and build a model building that,
when placed in direct sunlight, will efficiently absorb and retain solar energy. Your model
does not have to resemble a conventional house, and should heat up as much as possible,
even though that might not be the goal in a real building.
Specifications:
● Any materials may be used (cardboard, wood, aluminum foil, Styrofoam, clay,
etc.)
● The minimum internal area will be 10cm X 10 cm X 10cm
● Maximum size (external): project must fit inside a box that is 40 cm on each side
● You must be able to insert a temperature probe to read the inside air temperature
● The model must sit flat on the ground and not be moved during the test (in other
words, you may not tilt it to receive sunlight more directly, prop it up to change its
angle, or rotate it to follow the sun’s apparent movement)
● You may not focus the sun’s rays on your thermometer or use any combustible
materials – no internal heat source
Design considerations:
● Angle of insolation (insolation: incoming solar radiation)
● Color and texture of surfaces
● Use of greenhouse effect (using windows to allow light in, but trapping longer
wavelengths radiated by heated materials inside)
● Insulation
● Use of thermal mass
● Sealing to prevent potential leaks/drafts
Hints/mistakes to avoid:
● Condensation/fogging of windows significantly reduces heating. Make sure your
structure is completely several days before the experiment so all materials are dry
● Heat will be lost through conduction on the bottom (your structure will be sitting
directly on the ground) so don’t forget to insulate the floor
● Reflective materials on the inside of your building may reflect light back out
through the window - when that happens the wavelength doesn’t change and the
reflected light will not heat your structure
● Check the diameter of our temperature probes and drill or punch a hole of that
approximate size - do this before adding any loose insulation (drilling through
insulation will result in a tangled mess on the drill bit and insulation being pulled
away from its intended use
Evaluation of designs:
All models will be tested under equal conditions. They will be placed in direct sunlight
for a minimum of 30 minutes. Temperatures are to be recorded at 1-minute intervals. The
models will then be quickly moved into the shade, where the temperature will continue to
be recorded as long as time permits. Later, the data will be graphed, and heating and
cooling rates calculated.
A performance score will be calculated as follows:
● 2 points for each degree (Celsius) above the ambient temperature
● 1 point subtracted for each degree of cooling in the first 10 minutes of cooling
● Any suggestions you have will be considered
Do this second calculation as well:
● [(Maximum temperature - temp. after 10 minutes cooling) ÷ Max. temp] X 100
Group report/lab write-ups: Include the following topics in your write-up:
● Introduction - paragraph including the reason for such a project (5)
● Sketch of your design (5)
● Explanation of how the 6 “design considerations” were incorporated. Be sure to
address all six (10)
● Strengths and weaknesses – at least one of each (5)
● Suggestions for improving your design – what could be done differently that
might help your design to work better (5)
● A graph of the temperature changes over the experiment (5)
● Performance score data/calculation (show work) (5)
● Discussion of how passive solar design concepts could be used to supplement the
heating of your own home (i.e. retrofitting or modifying your home) (5)