Long ago snow and ice, cool streams, springs, caves and cellars were used to refrigerate (to cool, freeze or make cold) food. Meat and fish were preserved in warm weather by salting or smoking.
The Chinese cut and stored ice in 1,000 B.C. Around 500 B.C. the Egyptians and Indians made ice on cold nights by setting water out in earthenware pots and keeping the pots wet.
In 18th century England, servants collected ice in the winter and put it into icehouses. The sheets of ice were packed in salt, wrapped in strips of flannel, and stored underground to keep them frozen until summer.
In the 1920s and 1930s, consumers were introduced to freezers when the first electric fridges with ice cube compartments came on the market. But mass production of modern fridges didn’t get started until after World War II.
Refrigeration technology improved in the 1950s and 1960s when new inventions like automatic defrost and automatic ice-makers first appeared.
Environmentally-friendly design became important in the 1970s and 1980s, which led to more energy-efficient refrigerators. Today, the fridge is Britain’s most popular appliance, found in more than 99% of homes.
A fridge keeps food cold by moving heat from inside to outside. A liquid flows around a circuit of pipes. As it flows it changes from a liquid to a gas. As it does so, it takes up heat from the food and air, making them cold. The pipes carry the gas behind the fridge, where it gives off heat to the surrounding air.