I’ve had this idea for a powerless fridge, and was wondering if somebody had ever seen anything like it, if anybody thinks it could work, if anybody would like to make it, or indeed, if anybody can understand it !!
It is quite simple, actually. It works using the same principle as a conventional fridge: A liquid changes into gas by absorbing heat from whatever is around it, in this case the air inside the fridge, which gets cold and refrigerates our food. This gas is enclosed into a closed circuit, and converted again into liquid.
In a conventional fridge the gas in converted into liquid by a motor (usually powered by electricity) which pressurises the gas. The powerless fridge uses gravity to put the gas under pressure and convert it into liquid.
Take a look at this drawing:
So, it is basically a steel cylinder with three cylindrical stones inside. The cylinder is connected to a fridge unit by an exit at the bottom for the liquid and an entry at the top for gas. Both the entry and the exit can be closed. At the top of the cylinder there are two stoppers, to keep the stones in place, or let them fall freely.
In the back of the fridge unit there is an expansion chamber. When liquid from the cylinder reaches this point, it expands into gas, absorbing heat.
The first picture is when the fridge is not working. The cylinder is full of gas. Now, let’s make it work:
-close entry and exit.
-Open stopper A and let stone 3 into stopper B.
-remove stone 1 from bottom (stone 1 lays on the floor, but its top closes the cylinder’s bottom), and place it in the top (stopper A on).
-Open stopper B. Stone 3 falls and presses the gas inside the cylinder into liquid.
-Open exit and entry. The liquid should get into the expansion chamber, expand, converting into gas by absorbing the heat, and back into the top side of the cylinder.
It would look like this:
When the liquid finishes it’s time to repeat as above.
Well, more crazy things have worked!! What do you think? What kind of gas? What would be the length of the cylinder needed? The stones’ weight?
And, apart from that, you can always get one of these: The two clay pots with damp sand in between…a beautiful thing!