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Surfer Chef Enterprises Solar Cooking, a Solution for Pollution |
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Surfer Chef Enterprises Solar Cooking, a Solution for Pollution |
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This solar oven is designed to use minimum material and to be used in places where the sun is
more or less overhead.
All you need is a hole in the ground, a bright sunny sky and reflective material.
Hopefully it can be used right away in Africa and other places where clean drinking water is a problem.
I have read that people dig for roots in these camps and that there are holes all over the ground.
If that's the case, then most of the work is already done.
An above ground, mud earthen frame can also be used, but that would require water to make the mud.
First I will give the results from the tests of two, in the ground, solar ovens.
One has a reflective white liner made out of .69 mil kitchen trash bags. The total cost of the bags needed to build an oven is 16 cents.
The other has a liner
made of the reflective Mylar from an emergency blanket.
Results of the white plastic lined oven: 22 January 2007
The white liner raised the temperature of 3 cups, (24 ounces) of water in a shiny black, 6 cup
covered container
from a starting temp. of 76F to 164F at the end of five hours. The starting time was 9:00 and the ambient temp was 50F.
The test ended at 2:00 and the ambient temperature was 70F.
It was very hazy, the UV index was 3, and the ambient temperature was between 50-72F.
The total temperture increase was 88F. on a 70F hazy winter day in
this uninsulated solar oven.
More than enough heat to Pastuerize water or to cook food.
It should work very well in Africa where there is a desperate need to Pasteurize drinking water.
UPDATE - 3 February 2007 - White Plastic Lined Oven
The idea is to place two cooking containers in one, in the ground solar oven.
One pot contained 24 ounces of water, and the other 32 ounces.
The starting temp. of the water was 68F. The ambient temp.during the test was 48-75F.
The sky was hazy and the UV index was 4.
The test started at 9:00 and ended at 1:15.
Results
The 24 ounces of water reached 164F, and the 32 ounces reached 158F.
In Africa, with ambient temps. of 80-90F, a clear blue sky, UV 10, and the sun high in the sky, two
containers of water or food will reach much higher temps. in this oven.
Water can be Pasteurized by heating the water in a range of 150F for 30 minutes or to 160F for about 15 seconds.
Test #2: The goal is to eliminate the plastic bag around the bottles.
The bottles and oven were setup as in test #1.
Two 16 ounce bottles were placed on an angle against the wall of the oven so that the length of
the bottle was facing the sun.
Results
Test started at 9:00 and ended at 1:15.The ambient temp. was 52-83F.
The bottles reached a temp. of 162F.
Notes:
The bottles were filled to just below the neck.
At 150F, there was little condensation in the ovens. Thirty minutes later, at the end of the tests,
the bag in the Test#1, and the oven cover
in Test #2 were full of condensation.
Due to the thermal expansion of water it will be possible to tell when the water is Pasteurized without the need for a thermometer.
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UPDATE 16 February 2007 - 3 Liter clear bottle
This test used the white plastic lined oven and a 3 Liter clear bottle.
A black plastic insert, (12" x 36") made from 1.2 mil trash bag material and 97 ounces of water
were placed into the 3 liter bottle.
The black plastic sheet was folded in half and a small rock was placed in the center of the fold.
This was then placed into the clear bottle and the water was added. The rock will keep the plastic from floating up as the water is heated.
The bottle was covered with a clear plastic bag and placed in the center of the oven. The top of the oven was covered with clear plastic.
Results
The test started at 8:00. The ambient temp. was 50F and the water temp. was 70F.
The sky was hazy with some passing high clouds.The UV index for the day was 4.
At 1:00 the water temp. was 152F and the ambient was 80F.
At 1:45 the water temp. was 159F.
The water level had risen up inside the neck of the bottle.
The volume of the 97 ounces of water had increased by 150 ml., in the temp. range of 70F to 159F .
This is a good indicator of when the Pasteurization temperature is reached without the need of a thermometer.
3 litres of water is 101.4 fluid ounces.
END OF UPDATE
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UPDATE 24 February 2007 - 2 Liter clear bottle
This test used the white plastic lined oven and a 2 Liter clear bottle.
A black plastic insert, (12" x 36") made from 1.2 mil trash bag material and 64 ounces of water
were placed into the 2 liter bottle.
The black plastic sheet was folded in half and a small rock was placed in the center of the fold.
This was then placed into the clear bottle and the water was added. The rock will keep the plastic from floating up as the water is heated.
The bottle was covered with a clear plastic bag and placed in the center of the oven. The top of the oven was covered with clear plastic.
Results
The test started at 8:15. The ambient temp. was 45F and the water temp. was 68F.
The sky has some haze.The UV index for the day was 5.
At 11:50 the water temp. was 150F and the ambient was 70F.
At 12:30 the water temp. was 160F.
At 1:40 the water temp. was 171F.
The water level had risen up to the neck of the bottle.
END OF UPDATE
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Material:
Now line the hole with your reflective material.(white plastic, Mylar or foil)
Put your container in a clear plastic bag ( may not be needed), then
place your cooking pot,(with lid) on the flat bottom.
Cover the hole with your clear plastic sheeting, to retain heat.
That's it. The sun will do the rest.
To protect the Foil or Mylar reflective material, lining the hole with cloth or plastic before the reflective material is added will extend the life of the oven. The white plastic material will not need another liner.
Each unit was tested as follows:
A cardboard model was built as in the sketch, and used above ground. Too much shade in my yard
for an in ground test. I had to move the oven 3 times. The oven will gain less heat this way because it is exposed to a cool breeze.
This can be concidered a worst condition test.The in ground oven will be well insulated by the earth.
The stove was titled south about 15 degrees, to get a better angle on the low winter sun.
Each pot was placed in a clear plastic bag.
The oven was then covered with a 2 mil clear plastic sheet to retain the heat.
Tests were conducted in Fullerton, CA, latitude of about 33 degrees, north.
Thanks for stopping by; have a good one.
Here's what you need:
An empty 15-16 ounce tin can
A sharp knife
Aluminum foil 6"x 12", three pieces
2 average size magazines
70% Rubbing Alcohol
Directions:
1. Roll the two magazines together and put them into the can.
This will make it easier to poke holes in the can.
2. Most cans have a 1" flat section at both ends and are ribbed in the middle.
Approximately 1" from the bottom of the can, in between the 1st and 2nd riblines cut 7 or 8 approximately
1/4" slots,
more or less evenly spaced around the can. Then open the slots to about 1/4" high by twisting
the knife tip in them.
3. About halfway up the can, cut another 5 or 6 holes around the can.
Remove the magazines from the can.
Each aluminum foil strips will be folded as follows to make a pot rest for cooking and allow the pan to be heated.
4. Fold the 6" side in half, 4 times so that the foil is about 12" x 1/2". Now fold the 12" length in half, 3 times.
When you have the three foil pieces about 1" x 1/2" fold them in half around the open end edge of the can,
as evenly spaced as possible so that half is on the inside and half is on the outside. Squeeze them tight to the sides of the can.
You should now have three evenly spaced foil "bumps" around the top of the can. If you place a pan on them you will notice a gap like a regular stove burner.
To try it out, ball up a small piece of paper,(like half a napkin) and put it in the bottom of the can.
Pour in one tablespoon of Rubbing Alcohol and throw a match in.
Each tablespoon will burn for approximately 6 minutes. Two or three tablespoons should cook most food.
Always use a covered pan if possible to retain heat.
This unit was tested using only 70% Rubbing Alcohol.
Use with adequate ventilation, on a non-flammable surface.
It may not be a thing of beauty and a joy forever, but it will get the job done.
Click here for Cloth Water Filter info.
Objective:
To make an emergency water filter, to clarify high turbidity water, out of readily available material,
that would be effective, dependible and take only minutes to construct.
This filter is designed to filter muddy/cloudy water. The only type of water that is likely to be available
after a natural disaster, especially in developing countries.
Excessive sediment or cloudiness will greatly reduce the effectiveness of any disinfecting process.
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Emergency Water Filter:
Filter Material Pack - Newspapers (6.25" x 22.5" X 40 sheets thick)
Type - Capillary/Syphon, continuous flow
Flow - 3 plus ounces per hour,(initially) from one filter pack.
One average daily newspaper of 60 pages will make 3 filter packs,
capable of producing
7 quarts of clear water per day.
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Filter construction details:
Twenty sheets of a standard American newspaper, were cut in
half lengthwise, yielding 40 sheets of approx. 6.25" x 22.5".
The sheets were put together so that the natural lengthwise fold was on the outside of each
length. This construction will prevent sediment intrusion
along the outside length of the filter pack.
The bottom of the paper that will be placed in the "muddy water" must be folded twice about
1" each time to form a crease near the bottom. This will prevent the sediment from entering
through the bottom of the filter pack.
Fold the length of the filter pack in half or use the natural fold of the newspaper.
One half of the paper length, (11.25") will be placed in the muddy water.
The filtered water collection container must be lower than the muddy water container.
The filtered water will flow from the end that is placed into a collection container.
Keep the filtering end several inches above the bottom and let the water drip into the collection container.
The filtering end should not be resting in the filtered water.
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Test unit:
A trough ( 26"x 20" x 6") was filled with muddy water to within 2" of the top.
The water was left to settle for two hours.
The filter was placed onto (floated on top) of the muddy water with the ends of the
40 sheets pointing up from the bottom end fold.
The filter sank at its own pace as
it absorbed water.
The end of the filter that drips the filtered water must be lower than the muddy water container for the filter syphon effect to work.
After about 2.5 hours the entire filter pack was wet and several ounces of water
were removed from the collection container.
This sample was very clear wih a slight yellow tint.
Test unit vapor tent:
Previous tests have shown the this filter will work better in a humid enviroment.
Left in bright sunlight or windy and low humidity conditions the surface of the filter pack
would evaporate water, reducing the output.
A thin white plastic sheet was used to cover the entire trough as well as the filter
and collection container. Care must be taken to ensure that the plastic covering does
not contact the filter pack. Any contact will start a water flow from that point,
bypassing the filter material.
The temperature range for this test was between 54-75 degrees F.
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Test Results:
The water collected from the filter had a slight discoloration but appeared very clear.
As the flow decreased the water became clearer.
The water flow through the filter for each measured period is as follows:
This water should be treated chemically or Pasteurized before drinking. It has not been tested for any pathogens present in the "muddy" water or in the filtered water. The filtered water was very clear with no noticeable odor. It should be noted that normal cooking destroys pathogens. This link will provide information on food and water borne bacteria and the heat needed to destroy them.
| Notes | Test Period | Flow | Flow Rate | Total Time | Total Flow |
|---|---|---|---|---|---|
| *** | Hours | Ounces | Ounces/hour | Hours | Ounces |
| *** | 8:30 | 27 | *** | *** | *** |
| A | 7:45 | 24 | 3.10 | 16:15 | *** |
| *** | 7:45 | 24 | 3:10 | 24:00 | 75 |
| A | 11:00 | 31 | 2.82 | 35:00 | 106 |
| A | 10:00 | 32 | 3.20 | 45:00 | 138 |
| A,B | 22:00 | 61 | 2.80 | 67:00 | 199 |
| *** | 13:00 | 36 | 2.77 | 80:00 | 135 |
| A | 11:00 | 32 | 2.90 | 91:00 | 167 |
| *** | 12:00 | 33 | 2.75 | 93:00 | 300 |
| A,C,D | 12:00 | 26 | 2.16 | 105:00 | 326 |
| *** | 13:30 | 28 | 2.07 | 118:30 | 354 |
| E | 12:30 | 22 | 1.76 | 131:00 | 376 |
| *** | 11:00 | 21 | 1.90 | 142:00 | 397 |
| A | 11:30 | 18 | 1.76 | 153:30 | 415 |
| *** | 14:00 | 23 | 1.64 | 167:30 | 438 |
Notes:
A = Added cloudy water,(slowly) back to the 2" starting level.The sediment in this water
had been allowed to settled for 12 hours before use.
B = Stirred water to raise sediment off bottom and muddy the water again.
(This was done to check filter degradation over the next several collection periods.)
C = The majority of the filter in the trough is covered with a layer of sediment extending from the
end of the filter to approx. 1" below the surface of the water.
D = The water appears to have less of a tint as the flow decreases.
E = Added "muddy" water, (slowly) up to the 2" starting level.
The most common emergency methods for making questionable water safe for drinking are:
1. Boil the water for at least one minute. Some recommend 3-5 minutes.
2. Use liquid household chlorine bleach (5.25% sodium hypochlorite) as follows:
For each quart of clear water add 2 drops. Add 4 drops if water is cloudy.
For five gallons of clear water add 1/2 teaspoon. Add 1 teaspoon if the water is cloudy.
Mix thoroughly and let stand for 30 minutes.
3. Pasteurizing water by keeping it at 161F (70C) for 15 seconds to destroy pathogens.
If present in the water, some parasites and viruses will not be destroyed by Pasteurization or the use of chlorine bleach.
CLOTH WATER FILTER
This filter is designed to filter muddy/cloudy water. It is based on the principle of capillary action
and the syphon effect.
This filter takes only a minute to set up using any size containers a person might have.
Any towel or cloth can be used.
The collection container must be lower than the muddy water container for this system to work.
Fill a container with muddy water, 2 inches from the top.
The fastest method of filtering out the sediment is to wrap the cloth in a piece of plastic sheeting.
The thin plastic sheeting can be
secured with string or tape around the cloth.
Place one half of the cloth, 12 inches or more, into the dirty water and drape the other half
on the outside of the dirty water container and place it above your collection container.
After a period of time, depending of the type of material, water will flow into the collection container.
Initially the water will be somewhat cloudy and contain fibers because the filtering cloth is being
cleaned as the water flows thru it.
Dampening the cloth will greatly speed up the initial flow thorough the filter,
as the fabric will absorb
all the water it can before the filtered flow starts.
For drinking, this water can be easily disinfected using household chlorine bleach, or by Pasteurization.
It can be used as is for cooking, since normal cooking temps. will kill most waterborne pathogens.
CLOTH FILTER TYPE
A damp, regular cotton T-shirt was folded so it was 3"x 30" and wrapped in a piece of thin plastic sheeting.
The plastic sheet was 14" long and 11" was on the outside of the container.
After it was saturated, this one T-shirt filtered very clear water at 3 ounces per hour or 2 quarts per day.
Four of these in a bucket would give a family about
2 gallons of clear filtered water per day,
ready to be disinfected for drinking or used as is for cooking.
As long as the dirty water container has water in it, the syphon will keep the water flowing thorough the filter.
The flow will be faster if the water level is kept high.
A thin worn cotton towel (24" x 42") was folded so that it was 3" wide and wrapped in a piece of plastic sheeting, 27" long with 15" outside of the container.
The water flow thorough this filter was 8.5 quarts in 24 hours.
A heavy, fairly new, cotton towel (24" x 42") was folded so that it was 3" wide and wrapped in a piece of plastic sheeting, 27" long with 15" outside of the container.
The water flow thorough this filter was 14 ounces per hour, or 10.5 quarts in 24 hours.
Without the plastic cover, in bright sunlight or windy and low humidity conditions the surface of the filter
would evaporate water, reducing or stopping the output.
As required, the filters can be backwashed by holding the filtering end up and the dirty end down then gently shake it for 30 seconds or so. This should wash much of the sediment from the cloth.
If needed for long term use, when the water flow thorough the filter becomes
too low, the filtering material can be dried out, the sediment pounded out of it and the filter reused.
If anyone finds this information helpful, please pass it along to others who may have need of it.
| Time | Temp. | Set-Up | Comments |
|---|---|---|---|
| 8:30 | 70F,21C | Six Qt.(5.7L) black pot with oven thermometer in the bottom. The pot is held off the bottom of the oven by three, 1" high rocks | Hazy Southern California summer sky |
| 9:00 | 180F,83C | ||
| 9:30 | 205F,95C | ||
| 10:00 | 230F,110C | ||
| 1:30 | 260F,125C | ||
| 2:00 | 260F,125C | ||
| 2:30 | 250F,121C | ||
| 3:30 | 245F,119C | ||
| 4:30 | 220F,105C End Test |
| Time | Temp. | Set-Up | Comments |
|---|---|---|---|
| 8:30 | 63F,17C | Ten inch dia.(25.4cm) by two inch deep frying pan, with ext. shiny sides, a brown bottom and black interior. An oven thermometer is placed in the bottom of the pan and clear piece of 1mil plastic sheeting, is used as a pan cover. A foil covered bowl (6"x1.75"),(15.3cm x 4.5cm) is used as a stand for the frying pan. | Clear Southern California fall sky |
| 9:00 | 195F,90C | ||
| 9:30 | 220F,105C | ||
| 10:00 | 235F,113C | ||
| 10:30 | 250F,121C End Test |
| Time | Temp. | Set-Up | Comments |
|---|---|---|---|
| 10:00 | 78F,25C | One gallon,(3.8L) ceramic cookie jar painted flat black and filled with two cups of water and one cup of long grain rice. The container is held off of the bottom of the oven by three, one inch (2.5cm) high rocks. | Hazy Southern California summer sky |
| 11:30 | ----- | ---------- | Rice is almost cooked |
| 12:00 | ----- | ---------- | Rice is cooked |
| Time | Temp. | Set-Up | Comments |
|---|---|---|---|
| 10:00 | 76F,24C | Two and 1/2 quart container painted flat black and filled with one quart of water and two cups of long grain rice. The container is held off of the bottom of the oven by three, one inch (2.5cm) high rocks. | Hazy Southern California summer sky |
| 1:00 | ----- | ---------- | Rice is cooked |
| Time | Temp. | Set-Up | Comments |
|---|---|---|---|
| 11:30 | 81F,27C | A dark green glossy Square pan, (8"x8"x2"). Placed 1.5 lbs. of ground beef (at 50F) into the pan and covered it with aluminum foil. The pan was placed on three 1" high rocks to keep it off the bottom of the oven. A meat thermometer was placed into the middle (coldest) part of the ground beef. | Hazy Southern California summer sky The combination of glossy, square pan and a reflective foil cover represents a worst condition test. |
| 1:30 | 162F,70C | ---------- | The recommended cookbook temp. for meatloaf is 161F,70C |
| 1:45 | 170F,78C |
| Time | Temp. | Set-Up | Comments |
|---|---|---|---|
| 9:00 | 50F,10C | Six quart pot, painted flat black. Placed an inverted pie pan into the bottom of the pot, and placed a 3 lbs. whole chicken on top of the pie pan and closed the pot. The pan was placed on three 1" high rocks to keep it off the bottom of the oven. | Clear Southern California winter sky. |
| 1:00 | ----- | ---------- | The chicken was cooked. Clear juice and no red meat. |
MATERIALS NEEDED:
1. Meat thermometer - Dial type - 6" long
2. Two aluminum soda cans - 12 ounce
3. Measuring cup
4. Scotch tape
ATTENTION TEACHERS: Because solar cookers do not have a flame,
students may think that they do not get very hot.
The students need to be told that solar cookers can get
HOT enough to cause BURNS.
Experiments for the Simple Solar Stove.
1a. Wrap one layer of black plastic around an aluminum can, secure plastic with tape.
1b. Insert the meat thermometer into the can.
Make sure that the end of the thermometer does not contact the inside wall of the can.
1c. Place the can on the stove about 1" from the reflector.
1d. Aim the cooker towards the sun.
1e. After five minutes take a reading. The can will be hot to the touch. Remove can from stove.
1f. Put the reflective Mylar over black base and tuck the extra material under the front of the stove.
1g. Place the can back on the stove and take a reading in five minutes.
1h. Place the clear bag over the can and take another reading after five minutes.
Q: What is the difference in the readings? Why?
1i. Remove meat thermometer and pour 4 ounces of water into the can, reinsert thermometer and take reading.
Place the plastic bag over the can.
Take a total of 3 readings, one every 5 minutes.
NOTE: You just made a solar hot water heater.
A household water heater on low setting is 120F. A very hot spa is 104F. Bath water is around 100F or less.
2. Repeat the same experiments using a plain aluminum soda can, or you can wrap a can in aluminum foil for more contrast.
Q: What is the difference in the readings? Why?
3. Place 4oz. of water into the "Glad" double lock bag, and remove as much air as possible from the bag.
Place it on the black base and aim the stove towards the sun.
Touch the bag every 5 minutes or so and notice that it is absorbing heat from the black paper.
Black metal is not the only material that can be used to heat with solar energy.
We hope that you had fun doing these experiments and that you will continue to expand your knowledge of science.
CONSTRUCT THE OVEN AS FOLLOWS.