In response to a friends challenge to make a solar cooker and prove it would work in the UK, the solar cooker shown below was built. Only scrap materials have been used, mainly based upon a piece of plastic mirror found in a skip
It is a box-type cooker with a central oven around which there is plenty of insulation. One side has a glass front and the mirrors channel additional sunlight into the box. The mirrors slope at approximately 45 degrees.
A potato and a carrot were cooked over the course of about 3 hours on a bright October day, with an average of approximately 90°C being maintained. More testing and data logging is required to see how well it performs.