<P> Domestic refrigerators and freezers for food storage are made in a range of sizes . Among the smallest is a 4 L Peltier refrigerator advertised as being able to hold 6 cans of beer . A large domestic refrigerator stands as tall as a person and may be about 1 m wide with a capacity of 600 L. Refrigerators and freezers may be free - standing, or built into a kitchen . The refrigerator allows the modern household to keep food fresh for longer than before . Freezers allow people to buy food in bulk and eat it at leisure, and bulk purchases save money . </P> <P> Before the invention of the refrigerator, icehouses were used to provide cool storage for most of the year . Placed near freshwater lakes or packed with snow and ice during the winter, they were once very common . Natural means are still used to cool foods today . On mountainsides, runoff from melting snow is a convenient way to cool drinks, and during the winter one can keep milk fresh much longer just by keeping it outdoors . The word "refrigeratory" was used at least as early as the 17th century </P> <P> The history of artificial refrigeration began when Scottish professor William Cullen designed a small refrigerating machine in 1755 . Cullen used a pump to create a partial vacuum over a container of diethyl ether, which then boiled, absorbing heat from the surrounding air . The experiment even created a small amount of ice, but had no practical application at that time . </P> <P> In 1805, American inventor Oliver Evans described a closed vapor - compression refrigeration cycle for the production of ice by ether under vacuum . In 1820, the British scientist Michael Faraday liquefied ammonia and other gases by using high pressures and low temperatures, and in 1834, an American expatriate in Great Britain, Jacob Perkins, built the first working vapor - compression refrigeration system . It was a closed - cycle device that could operate continuously . A similar attempt was made in 1842, by American physician, John Gorrie, who built a working prototype, but it was a commercial failure . American engineer Alexander Twining took out a British patent in 1850 for a vapor compression system that used ether . </P>

Who invented refrigerator & what year was it invented