Please note: that the pictures and the cooker used in the tests from December 2008 are of the prior model of the BTSA. It features a square insulated cook box and is larger than the next generation prototype. Since 2008 the original design was improved, with a round cook box, based on field-testing feedback, making it lighter and smaller, without compromising efficiency.
The test was conducted comparing it to 3 three commercially available and widely used solar cooker in December 2008.
Testing periods: December 18 to 28, 2008 with vegetable oil and water.
December 17, 18,19 and 20: 1 liter of vegetable oil (soy bean oil) was heated in each unit with constant monitoring of the temperature in 15 minutes intervals.
December 22, 23, 24, 27 and 28: 3,78 liters or 1 US gallon of water were brought to a boiling point of 100˚C (212˚F). After reaching the boiling point, the water was replaced with ambient temperature water, to determine how many cycles of boiling water could be achieved in one day.
Location: On the rooftop of a 4 story building in Honolulu, Hawai‘i (21˚17.44N 157˚49.89W, altitude 20m) which receives an annual average of 500 cal/cm. The roof was covered with tar and gravel and sheltered by a 1.07 m high wall. All four units were tested, weather permitting.
Setting: All four cookers were set up facing the sun and were adjusted manually, a few times per hour to optimize each unit facing the sun. Testing started in the morning and lasted until the sun was at an angle too low to reach the solar cookers (unless total cloud cover made adequate testing impossible earlier).