Simple Homemade Solar Cookers for Easy Solar Cooking

Fun-Panel Cooker Construction Plan

The Funnel solar cooker, originally introduced by Professor Steven E.

Jones, is very efficient in capturing sunlight with its 60 degree conical

reflecting surface.  However, the Funnel solar cooker has an unstable

shape that makes it difficult to keep the cooker and the pot in position. 

In addition, it is also not possible to fit a regular size cooking pot into a

regular size Funnel cooker because of limited space at the lower end

of the cooker.  In order to retain the very efficient conical reflecting

surface, but eliminate the above mentioned disadvantages, I came up

with a hybrid Fun-Panel solar cooker.



The Fun-Panel solar cooker incorporates features from the Panel

cooker into the Funnel cooker.  The Fun-Panel cooker can also be

placed in two different positions to better capture sunlight at different

Sun's altitudes.




The construction materials required to make a Fun-Panel cooker are

simple and low cost.  I made my Fun-Panel cooker from a used

cardboard box that measures about 50cm on all edges.  One cube-

shaped cardboard box has enough cardboard material for making

two Fun-Panel cookers.  Other construction materials required are

one short string, paper tape, aluminum foil and glue.  If you use

cardboard box with different dimension, all you need to do is to factor

the dimensions given in this instruction to suite your box's dimension


To construct, cut the cube-shaped cardboard box to obtain two large

rectangular panels and one small panel as shown in Figure 1 below.



The 'Fun-Panel' plan was originally created using the Corel Draw

software.  Click the link below for a .cdr (Corel Draw) copy of the plan. Plans.cdr


Each large rectangular panel is made up of one square face of the box

together with one cover flap.  Next glue aluminum foil onto one side of

the two large rectangular cardboard panels.  Draw all the fold lines and

cut lines, according to Figure 1 above, onto the rectangular cardboard

panels.  Next cut along the cut line and then fold along the fold lines.


Join the two large rectangular cardboard panels together, according to

Figure 2 below, to form the cooker.   



Next glue the small cardboard panel to the lower edge of the square

panel, located in the middle of the cooker, according to Figure 3 below. 



After the glue has dried, bring the lower edge of this square panel

forward by a distance equals to 2/5 the length of the square panelís

edge (this ratio is critical as it defines the final shape of the cooker). 

Punch two holes through both the small cardboard panel and the

adjacent rectangular panel, and tie them together with a short cord in

order to keep them in position.  The construction of the Fun-Panel

cooker is now completed. 




For low Sunís altitude cooking, between 35 and 50 degrees, place the

cooker down, with the rectangular panel on the floor, as shown in Figure

4 below.  For very low Sunís altitude cooking, below 35 degrees, raised

the pot by 2 to 3 inches above the base to better capture the sunlight. 



With rising sun angle, between 50 and 70 degrees, flip the cooker

around such that the square panel, in the middle of the cooker, is now

horizontal, and place the cooker on top of a small box (a box with 5-

6 inches in height is now required).  See Figure 5 below. 



The small box serves to support both the cooker and the cooking pot

in this high sunís altitude setting.  For very high sunís altitude cooking,

above 70 degrees, loosen the short string that holds the small cardboard

panel to the rectangular panel.  Tilt the vertical, rectangular panels slightly

backward until the pot receives maximum reflected sunlight.  Tie the two

ends of the string together to hold the rectangular panel in that position.


To cook, put foods inside a black metal pot, and cover it with a clear

glass lid.  Enclose the pot in a clear heat-resistant plastic bag.  Set the

cooker according to the Sunís altitude, and face it towards the Sun.

Place the cooking pot in the cooker and start cooking. 


The Fun-Panel cooker is also capable of cooking, without the clear

plastic bag enclosure, if you have good sunshine.  A test done in

Singapore, without the use of a greenhouse enclosure, have recorded

a maximum empty pot temperature of 130 degrees C.   The 4-liter size

pot used has a clear glass lid.  The cooker was set to the high-sun

angle setting, and the Sun's angle was at 55 degrees when the

temperature was taken.


Fun-Panel cooker can be folded flat by first untying the string and then

folding the middle square panel upward so that the cooker can be

drawn together for ease of storage.  I hope that you will find the Fun-

Panel cooker to be an interesting and user-friendly solar cooker.



Teong Tan

6 January 2008


Fun-Panel Modifications/Upgrades

I have received several success stories from people who have built and

used the Fun-Panel cooker.  Their positive feedbacks have prompted me

to take a closer look at the cooker design for further enhancement.

Several modifications have been identified for incorporation, individually

or together, into the original Fun-Panel design.


The first modification is to add a few more folds and cuts to the three flat

panels, located in the middle section of the cooker.  This modification will

further enhance the efficiency of the cooker reflectors.  See diagram below

for the additional folds and cuts required.


           Picture of the modified Fun-Panel reflectors

The second modification is an alternate method of tying the center panel

to the base panel in order to eliminate the requirement for the small

cardboard piece in the original design.  See diagram below for more details.

The third modification is to add an adjustable reflector-support, made from

cardboard and rubber bands.  The adjustable reflector-support eliminates the

need to tie the center panel to the base panel, and provides the cooker with

the freedom to tilt at various angles to better capture the sunlight.  The center

panel becomes the permanent base for the pot with this change added.


The photos and diagram below show the adjustable reflector-support

supporting the cooker at various tilt angle positions.



       Cooker at low tilt angle                  Cooker at high tilt angle



Teong Tan

1 July 2008