How does an automatic ice cube maker work? --- Pawlak, North Tonawanda, N.Y.
Think about how you make ice in a normal (manual) ice cube tray:
1) You fill it with water
2) You let the water freeze
3) You remove the ice.
An automatic ice cube maker does the same kind of thing. In one of the most common designs, the ice maker creates crescent-shaped cubes.
There is a solenoid valve that lets water into the tray. The amount of time the valve is open controls the size of the cubes. The tray is made of aluminum and has a temperature sensor on it. While the water is freezing, the tray's temperature will be 32 degrees F. Once the ice is solid, the temperature will fall below 32 degrees and it is time to eject the ice.
A heating coil under the aluminum tray heats the tray to detach the ice. Then a motorized arm slowly rotates to push the ice out of the tray. Once the ice is ejected, the cycle repeats.
For more info see: How Icemakers Work