Solar cooker are used in a lot of developing countries where fuel is in short supply but where there is abundant sunshine.Even in the UK,the amount of energy reaching each square meter of the ground can reach 4.5 to 5kWh per square meter per day in july.There is enough energy to heat the water for a large hot bath.This energy can also be captured and concentrated by a solar cooker.
During internship with WWF we have learned how to make solar cooker and here I will demonstrate as I learned so lets go green.
There are many solar cooker designs,but this is one of the simple and most popular.In fact it is so simple that people sometimes forget that temperature inside it can reach over 100 degree C,so make sure that you wear oven gloves when handling it.it is also a good idea to wear sun glasses as there can be a lot of glare from the reflective surfaces.
Building Your Own Solar Cooker
1.Before you start paint the inside of your baking tin with the matt black metal paint and allow it to dry.
2.The solar energy funnel: using a large pair of scissors or a craft knife,cut two sets of cardboard panels to the any dimension you want regrading size
3.Lay out the panels
as they are going to be assembled and using a small piece of cardboard.spread the thin layer of PVA glue over the surface of one the panels which will form the reflective surface
4. carefully lay sheet of tin foil onto the glue and smooth them down.try not to tear the tin foil and make sure that the shiny side is facing upward.
5.Repeat for the other panels.
6.When all of the panels have been coated on one side with tin foil assemble them into a funnel shape with the tin foil on the inside of the funnel join them together with the duct tape to make a solar energy
funnel show in the picture above.
THE COOKING BOX
1.Stand your solar energy funnel upright in a photocopier paper box.
2.When the box and funnel are lined up straight,duct tape the box in position you may also want to tape up any holes in the box
3.Fill the box with shredder paper or cardboard to act as insulation but leave enough space to fit the foil baking container
4.Place the baking container in position and wedge it in the place with the pieces of cardboard
5.When the baking container is in position the toughened glass sheet should rest on top try to minimize any air gaps as the cooker will lose heat through these.
YOUR SOLAR COOKER IS READY FOR TESTING
1.Your cooker will work best on a warm day to get it working angle it towards the sun and just wait you may have to use a few stones and what ever else is to hand to achieve the correct angle don’t look at the sun while you are doing this.
2.Place an oven thermometer in the baking container and take temperature readings at regular time intervals be care full as you do this because the inside of the cooker will be hot and their may be considerable glare from the reflective surface of the funnel a much more comfortable way to do this is with the data logger and temperature prober
3.The cooker should be taken through the cooking cycle at least two or three time before food is put in it to bake off any impurities when food is placed in the cooker it should be held in a clean heat- proof container and not place directly into the painted foil baking container
The use of oven bags is recommended.
Your Solar cooker is ready.