The solarchill probably works for what it was intended because the unit would not be openned very often, thus keeping it cold inside. Make a refrigerator out of it and it will be no good, people would constantly be openning it, stand there thinking of what they want to take out and letting all the cold air go out the bottom of the openning.
It hards to get folks to understand that "cold" flows down and each time you open the unit most of the cold air falls out. Thus the principle of the open cold food units in the supermarkets in the states, the top is open, the cold will not fall out, thus food stays cold even tho there is no door to the cold food units.
The more packed a refrigerator is maintained, the more it stays cold when the door is openned. As the cold in the food will not instantly leave it.
I keep plastic bottles filled with water in the freezer, it the same as blocks of ice that they used in the old days with "Ice Boxes", thus keeping the food cold even when the electric is off.