Note: The yellow line in this graph illustrates how the “ideal” curve would look like is this would have been a rather cloudless day with full sunshine. The curve used as a baseline for the other days is based on the data collected on December 23, the day with the most boiled water cycles during the testing period.
The World Meteorological Organization defines sunshine as direct irradiance from the Sun. “solar irradiance” measures the amount of solar energy that arrives at a specific area at a specific time. A pyranometer, the SDL-1 Solar Data Logger was used to determine how much solar power could be produced from the available sunlight (solar insolation) at the test site every day. With the SDL-1 data is logged as solar irradiance in Watts per square meter and cumulative incident solar energy in kilowatt hours per square meter. In plain English: When it is cloudy the curve drops and when the sun comes out the curve goes way up.
SOLAR COOKER TESTING: DECEMBER 23, 2008:
Setting: Boiling batches of water of 1 US gallon (3.78 liters) as many times as possible in all four solar cookers. Temperature was measured at 30-minute intervals and at boiling point for each unit.
Goal: To establish how many heating cycles, reaching 212˚F/100˚C can be achieved in one day by each unit. After the boiling point had been reached the water was immediately discarded and replaced with a fresh batch of ambient temperature.
Set-up: CooKit and Sun Oven aluminum pot with glass lid. SK14 closed black pot with solid lid. BlazingTubeSolarAppliance: enamel pot with lid. This data represents the best day with direct sunshine during the testing period.
Time frame: Testing (data collection): 9:45h to 17:07
Charts: Y-axis: The charts below show the water temperature in degrees Fahrenheit (boiling point for water is 212˚F/100˚C) for each cooker tested.
X-axis: Indicated the time it took to boil each 1 US gallon (3.78l) of water. The curve drops down to 80˚F if the water was replaced with ambient temperature water.
TABLE: Water heating cycles 1 US gallon (3.78 liters) reaching 212˚F/100˚C per day
Dec 22 '08
The BlazingTubeSolarAppliance completed 8 gallon boiling cycles for a harvested heat energy total of 8656 BTU.