Refrigerator

In early refrigerators, the compressor unit was located on top. Now, it is hidden inside.

From hauling chunks of ice down mountains to opening a refrigerator door, chilling out has become a lot easier.

The COOLEST invention of them all

The big freeze

Before refrigerators, people kept food from spoiling by storing it in cool, dark places or in a hole packed with ice or snow brought from the nearest mountain or frozen lake. Later on, rich families had specially built icehouses, with ice often imported in blocks from overseas. The trade in ice continued into the 1950s—this iceman is supplying ice to businesses from his truck.

First fridges

Did you know? In 1841, American doctor John Gorrie invented a refrigerator to cool feverish patients. It was the forerunner of air-conditioning.

In 1748, Scottish physician William Cullen discovered that evaporating ether could create freezing temperatures because evaporating liquids absorb heat. The first chilling machine, invented by American engineer Jacob Perkins in 1834, used this principle. Soon, industrial reFrigerators were cooling beer and meat. Domestic models It paved th became available in the 20th century. e way for...

Cooling units for

refrigerated trucks were introduced in the 1930s, making perishable goods Several shelves stored food, and there was a small compartment for ice.

First introduced into stores in the 1870s,

refrigerated display cases kept food fresh longer.

General Electric first made and sold this affordable steel fridge in 1927, finally making the refrigerator a common household appliance. Until 1929, refrigerators were deadly—they used poisonous gases as coolants and were responsible for several deaths. As a result, a safer chlorofluorocarbon (cfc) called freon was used to cool refrigerators. It was not harmful to human health, but later scientists realized that CFCs were destroying the Earth’s ozone layer. Modern fridges use a less harmful coolant to reduce the environmental impact. They can also be recycled safely.

HOW A refrigerator works by changing a substance called a coolant from IT WO R KS a liquid to a gas and back again. The liquid passes through an expansion valve, which turns it into a cold gas. The gas absorbs heat from the refrigerator’s contents, keeping them cool. The gas is compressed into a liquid as it leaves the refrigerator, which heats it up. The liquid loses heat to the room before passing through the expansion valve again. Expansion valve

Compressor Condensor coil

Evaporator coil

Did you know? German physicist Albert Einstein invented a refrigerator in partnership with his former student Leo Szilard and patented it in 1930.

American Clarence Birdseye invented a method of flash freezing food in 1929. Not long afterward, domestic freezers became popular. How it changed the world Chilling food keeps food fresh and safe for longer periods of time. This has changed customer shopping habits—people no longer have to go shopping every day, saving time and effort.

The first large-scale air-

conditioning unit was invented in 1902 by American inventor Willis haviland carrier. It used the same principle as the refrigerator.