The BYU Solar Cooker/Cooler | Page 7

see when the water is boiling - then it is
safe for sure.
Think of all the lives that can be saved simply by pasteurizing water
using a simple Solar Cooker!

VIII. Safety
Safety was my first concern in designing the Solar Funnel Cooker, then

came low cost and effectiveness. But any time you have heat you need
to take some precautions.
-The cooking vessel (jar) is going to get hot, else the food inside won't
cook. Let the jar cool a bit before opening. Handle only with gloves or
tongs.
-Always wear dark glasses to protect from the sun's rays. We naturally
squint, but sunglasses are important.
-Keep the plastic bag away from children and away from nose and
mouth to avoid any possibility of suffocation.

IX. Cooking with the Solar Funnel Cooker
What do you cook in a crock pot or moderate-temperature oven? The
same foods will cook about the same in the Solar Funnel Cooker
--without burning. The charts below give approximate summer cooking
times.
The solar cooker works best when the UV index is 7 or higher. (Sun
high overhead, few clouds.)
Cooking times are approximate. Increase cooking times for partly-
cloudy days, sun not overhead (e.g., wintertime) or for more than about
3 cups of food in the cooking jar.
Stirring is not necessary for most foods. Food generally will not burn in
the solar cooker.
VEGETABLES (Potatoes, carrots, squash, beets, asparagus, etc.)
Preparation: No need to add water if fresh. Cut into slices or "logs" to
ensure uniform cooking. Corn will cook fine with or without the cob.
Cooking Time: About 1.5 hours
CEREALS AND GRAINS (Rice, wheat, barley, oats, millet, etc.)
Preparation: Mix 2 parts water to every 1 part grain. Amount may vary

according to individual taste. Let soak for a few hours for faster
cooking. To ensure uniform cooking, shake jar after 50 minutes.
CAUTION: Jar will be hot. Use gloves or cooking pads. Cooking Time:
1.5-2 hours
PASTA AND DEHYDRATED SOUPS Preparation: First heat water to
near boiling (50-70 minutes). Then add the pasta or soup mix. Stir or
shake, and cook 15 additional minutes. Cooking Time: 65-85 minutes
BEANS Preparation: Let tough or dry beans soak overnight. Place in
cooking jar with water. Cooking Time: 2-3 hours
EGGS Preparation: No need to add water. Note: If cooked too long,
egg whites may darken, but taste remains the same. Cooking Time:
1-1.5 hours, depending on desired yolk firmness.
MEATS (Chicken, beef, and fish) Preparation: No need to add water.
Longer cooking makes the meat more tender. Cooking Time: Chicken:
1.5 hours cut up or 2.5 hours whole; Beef: 1.5 hours cut up or 2.5-3
hours for larger cuts; Fish: 1-1.5 hours
BAKING Preparation: Times vary based on amount of dough. Cooking
Times: Breads: 1-1.5 hours; Biscuits: 1-1.5 hours; Cookies: 1 hour
ROASTED NUTS (Peanuts, almonds, pumpkin seed, etc.) Preparation:
Place in jar. A little vegetable oil may be added if desired. Cooking
Time: About 1.5 hours
MRE's AND PREPACKAGED FOODS Preparation: For foods in dark
containers, simply place the Container in the cooking bag in place of
the black cooking jar. Cooking Times: Cooking time varies with the
amount of food and darkness of package.

X. How to Use the Solar Funnel as a Refrigerator/Cooler
A university student (Jamie Winterton) and I were the first to
demonstrate that the BYU Solar Funnel Cooker can be used--at night

--as a refrigerator. Here is how this is done.
The Solar Funnel Cooker is set-up just as you would during sun-light
hours, with two exceptions:
1. The funnel is directed at the dark night sky. It should not "see" any
buildings or even trees. (The thermal radiation from walls, trees, or
even clouds will diminish the cooling effect.).
2. It helps to place 2 (two) bags around the jar instead of just one, with
air spaces between the bags and between the inner bag and the jar.
HDPE and ordinary polyethylene bags work well, since polyethylene is
nearly transparent to infrared radiation, allowing it to escape into the
"heat sink" of the dark sky.
During the day, the sun's rays are reflected onto the cooking vessel
which becomes hot quickly. At night, heat from the vessel is radiated
outward, towards empty space, which is very cold indeed (a "heat
sink").
As a result, the cooking vessel now becomes a small refrigerator. We
routinely achieve cooling of about 29 degrees Fahrenheit (10 degrees
Celsius) below ambient air temperature using this remarkably simple
scheme.
In September 1999, we placed two funnels out in the evening, with
double-bagged jars inside. One jar was on a block of wood and the
other was suspended in the funnel using fishing line. The temperature
that evening (in Provo, Utah) was 78 degrees Fahrenheit. Using a
Radio Shack indoor/outdoor thermometer,