In my engineering class, we have to boil water using only solar power (no solar cells). Any suggestions?
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Answer:
You can try a classic solar cooker design this is just a black box that has a foil interior shaped is a parabola with the water at the vertex. Try this site it has some good pictures and details! Do not forget to tag your sources! Also try to place the water in a vacuum as previously mentioned, not a perfect vacuum but even a slight one will help.
use a magnifying glass
just wait for a really hot day and let the sun do it directly
get a big *** magnifying glass like the ones in the back windows in big RV's. That works like a charm.
Place a piece of black sheet metal in the container and train a magifying glass on the metal, the water will boil from the heat generated on the metal.
Boiling by solar power has 2 distinct advantages:
1.Apart from boiling, it will remove bacteria also.
2.It is very economical.
with the application of vacuum, you could get the water to boil at a low temperature very rapidly--of course it won't be hot enough for coffee or tea.
Mirrored parabolic trough with a pipe down the center.
You don't say what limits are on you.
The larger light-gathering area you have the better. You can buy 12"x12" mirrored tiles fairly cheaply. You can make a plywood parabolic shape to hold them. If you can put in enough light, you can dispense with insulation.
Search the interent for "solar furnace" "solar oven" "solar AND parabolic"
It might be cheaper to buy a 5' mirror and cut it into 1'x1' pieces. If you need to save money, make a paraboloid (like a satellite dish) from cardboard and line it with aluminum foil. The thing to do is to think of a very large light gathering area with the light accurately focused on a single point.
At a home improvement store, you can get termite shield cheaply. It is about 14" wide, maybe 16" wide, lightweight aluminum. Polishing it with silver polish would help make it shinier. You would have to back it up with plywood to make it hold the right shape.
You can make the parabola in the form of a dish or in a strip like you see on rotating radar antennas on ships.
You can do it in two ways.
1. Using parabolic reflector. Use a highly polished metal sheet and give it a parabolic shape. And then at focal point (i don remember right name may be) or the point at which the rays gather, place water in either a metal container or pass the water through a metal pipe(this requires pump). You can calculate the sheet dimensions and bending angles using parabol's equation.
2. Use heat absorbers:- Here you have to use black color as a heat absorber material. Although I doubt whether it can boil water or not..
And the best way is to combine 1 and 2..
Hope this helps..
Use a convex mirror & focus it on to the water. Try wrapping a polytene cover over the vessel to get better results.
If it is possible to reduce the pressure around the container you could boil the water at a much lower temperature. You could use the heat from the sun to boil the water, in conjunction use the panels to power a vacuum pump to reduce the pressure around the water.
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