A double-glazed flat-plate collector covered with a selective surface - Maxorb foil - was used as the power source for a solar cooker. Coconut oil was used as the heat transfer fluid. At the highest part of the thermosyphon loop is an oil bath in which two cooking pots are immersed to facilitate good heat transfer between the working fluid and the cooking pot. For simplicity, circulation is by natural convection; there are no pumps in the system. Temperatures of approximately 150°C can be achieved between 10:00 hr and 14:00 hr under insolation conditions of 25 MJm - 2 day - 1 with a peak value of 1000 Wm - 2 .