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OS:Solar Funnel:Data

Lasted edited by Andrew Munsey, updated on June 14, 2016 at 9:42 pm.

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Data relating to OS:Steven E. Jones Solar Funnel for Cooking

Tests of solar cookers in the Bolivian Altiplano

Source: http://solarcooking.org/scl_designs.htm

As mentioned here some time ago, the BYU Benson Institute arranged to have several solar cookers taken to the Altiplano in Bolivia and tested there.I have just received the report, results of which follow.

The tests were done by a group of 14 college students at the University of San Andreas. Tested were:

# Solar box cooker which I purchased from SCI then sent on to Bolivia

# Large 70-cm diameter (top) solar-cone cooker developed at BYU, with Al-foil glued onto cardboard (45-degree opening angle).

# Medium, 49-cm diameter (top) solar-cone cooker developed at BYU, with aluminized-plastic glued onto a thicker polyethylene cone (45-deg. again).

# "Eleanor's solar cooker. It is a piece of cardboard covered by aluminum paper. The piece of cardboard is bent to direct solar rays into the cooker." -- from the report (translated into English) Have asked for details about this cooker -- the nice thing is that a student looked at what we sent, then designed her own cooker based on this information. The cooker is evidently just a blackened pot with some kind of transparent hood around it -- trying to get details.

Results:

"The oven pasteurized the water in 110 minutes. The eggs were then added to be cooked. They were not dooked until noon. This is the reason why the oven was not used in the other tests."

I sent WAPI's to show when water would be pasteurized, that is, when the wax melted in the WAPI, the time elapsed was noted.

"The large cone took 130 minutes to pasteurize the water and did not cook the eggs. Its inefficiency may be a result of the lack of reflection in the surface."

The medium-size cone had a good performance. It pasteurized the water in 50 minutes, cooked the eggs in 70 minutes (same water), cooked rice in 75 minutes (same water). To cook rice with water at room temperature will take a little less than 110 minutes."

This shows the importance of higher reflectivity: the smaller cone worked much better than the larger cone, clearly due to the higher reflectivity of aluminized-plastic.

"Eleanor's [cooker] was the best cooker. It pasteurized the water in 50 minutes, cooked the eggs in 100 minutes with ambient-temperature water, and cooked rice in 160 minutes with ambient-temperature water."

To me, the data seem to suggest that Eleanor's cooker was a the same or slower than the medium-sized solar cone-cooker but for some reason the students found it to be the best. I hope to learn why. In any case, I'm pleased that Eleanor took the initiative to build her own solar cooker -- that is key to the successful spread of solar cooking, I think -- personal involvement and enthusiasm. So I'm happy that solar cooking has been experimented on by University students in Bolivia. The BYU Benson Institute will continue to support and encourage solar-cooking there.

--Steven Jones

BYU Physics Dept

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