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The Challenge: Make distilled water from seawater using solar power



How much energy would it take to boil the kettle?

A standard kitchen kettle takes about 2000 Watts of electrical power. The energy available from the sun depends on how much air the light has to pass through. Obviously the sun is hotter on the equator than at other latitudes, whatever the time of year. At the equator when the sun is straight overhead the power available from the sun is about 1000 Watts per square meter (1kW/m2). So if you have a parabolic mirror that has an area of two square meters and you use it to focus the energy on to the bottom of a kettle you will achieve the same sort of power as you would from the electricity socket with an electric kettle.

Our mirror only had an area of one square meter but unlike the kitchen kettle whose job is to boil water we don't need to actually get the water boiling to produce a vapor that we can condense to form steam.

Our parabolic mirror and kettle