Spring 2009

This semester, the solar oven team tried to determine the significance of several different
parameters on cooking efficiency. The tests involved running several "standard" tests in the
1-D scale up of the original oven and comparing their results with those from non-standard
tests. The standard test involves measuring the amount of time it takes to heat 5 pounds of
water in a single black pot from 40°C to 95°C, and is a simplified adaptation of the
procedure outlined in a report by the American Society of Agricultural Engineers, "Testing
and Reporting Solar Cooker Performance" (1). The ultimate goal of these tests was to
identify the important parameters that contribute to heat transfer to the water, optimize
them, and provide suggestions for improvements for future cooker designs.

At the beginning of the semester, the team listed the following parameters as ones that
could be of interest: total mass of water in the oven, oven volume, oven height, distance of
black plate from the lights, area of the glass, area of the black plate, the effect of wind,
number of pots, pot arrangement, pot size, ambient temperature change, and inside wall
temperature. Of these, the group decided to focus on changing the number of pots used in
the oven, the total mass of water in the oven, and pot arrangement. By testing various pot
arrangements, we could determine the optimal arrangement for cooking.

Additionally, while not recognized as a major variable in the beginning of the semester, the
group had the opportunity to test the effectiveness of silicone sealing around the glass in
the presence of wind. This was done using the 1-D scale up of the original oven by running
a standard test with two fans either off, or on at low or medium speeds both before and
after the application of silicone. If silicone were determined to be insignificant, it could be a
cost cutting measure for solar ovens construction.

To make the measurements for the experiments, the three major tools used were
thermocouples to measure temperatures, strain gauges to measure the strain of the glass
on the inside and outside of the oven, and an anemometer to measure wind speed.
Additionally, a pyranometer was used to measure the insulation at each test, though this
data was not actively used in the data analysis.