Refrigeration is the action of creating cooling conditions by removing heat. It is used for preserving food by slowing bacteria growth.

• Around 1000BC, the Chinese used to cut and store ice.
• Five hundred years later, the Egyptians and Indian...

• 1720s. Scottish doctor William Cullen saw that evaporation had a cooling effect.
• 1748. Cullen demonstrated his ideas by evaporating ethyl ether in a vacuum.
• 1805. Oliver Evans designed a refrigeration machine that used v...

Refrigerators today work by evaporating liquids.

The liquids are pushed through the refrigerator through tubes and begin to vaporize. As the liquids evaporate, they carry heat away with them as the gases travel to a coil outside the refrigerator. Here the heat is released....

• The first refrigerators contained flammable, toxic, and highly reactive liquids and gasses.
• Most refrigerators use hydrofluorocarbons (HFCs), which are safer than Chlorofluorocarbons (CFCs). CFCs are known to be harmful to the ozone layer.
• Refrigerators should be set at a ...

New technologies in refrigeration include solid-state refrigerators and refrigerators that use magnets.

• Solid-state refrigerators use the refrigerator's entire surface to slowly get rid of the heat. Solid-state refrigerators are also free from harmful materials and l...