Brief History of Refrigerator
Some of us may remember from the early 1950’s that we had a fridge in the house. It was not a real refrigerator, but just a big wooden box lined with metal. In the summer the ice man came regularly and placed an ice block in the box, so it was possible to keep the fresh and chilly.
Since the Middle Ages, in the cold countries, people harvested the ice in the winter and wrapped it in insulating straw. Thus it could be used in the hot summer months. This traditional technique was used far into the 19th century, before it developed into a large and profitable cooling industry.
By the end of the century, exporting ice cubes was a main occupation in northern countries. They were transporting the ice to Britain and other countries with hundreds of ships in form of fleets. The market also grew in the United States, where large ice batches were shipped with isolated ships and rail cars from the northern regions to the south-states – and even as far as hot Cuba. Between 1843 and 1856, the consumption of ice in New York City exploded from 12,000 tons to 100,000 tons.
Freezing water artificially?
The supply of natural ice stopped because of huge demand. This naturally gave rise to technological innovations. People began researching for a way to artificially freeze the water in order to avoid the inefficient and expensive transportation of natural ice.
There were attempts to produce artificial ice already in the 1700s. Scottish chemist William Cullen (1710-1790) had designed a small ice-machine using ether. When the ether evaporates after boiling it was possible to freeze small amounts of water to ice. French engineer Ferdinand Carré (1824-1900) patented the first practical ice-machine in 1859. His machine was dissolving some amount of ammonia in the water which results in producing 200 kg of ice per hour. In 1877, a ship equipped with Carré’s refrigerators transported frozen meat from South America to Europe for the first time.
Such transports from the southern continents became widespread soon. Between 1882 and 1887, 172 ships transported frozen lambs from New Zealand to Great Britain. The new refrigerators revolutionized both transport and storage of meat. Finally, the natural ices in the cold stores was phased out in the early 20th century.
Carl von Linde invented the refrigerator in 1876
While the steam engine‘s development in the 1700s was essentially on empirical basis, the refrigerators in the 19th century stood in debt for a scientific understanding of the heat as an energy form. The theory behind any kind of heat and cold machines is the main subject of thermodynamics, which was fully developed in the 1860s and proved to have important role on technological innovations.
The German engineer and professor Carl von Linde (1842-1934), combined scientific knowledge with practical and business sense. In 1876 he designed a cooling machine that initially attracted the major brewery companies, including Carlsberg. In the so-called compression machine, a refrigerant (like ammonia or sulfur dioxide) was evaporated at low pressure, after which it was condensed at higher pressures. The process was repeated cyclically and continuously.
Linde’s machine contained the three key components still found in a refrigerator:
His company achieved a great commercial success and soon developed into a far-branched industrial group that still exists and currently employs 60,000 employees. During the industrial exhibition in Nuremberg in 1892, Linde presented a skating rink made of artificial ice. How amazing: You could ski on ice in the middle of summer.
Entrepreneur Linde did not produce refrigerators just for the brewing and food industry. He was also a pioneer in a whole new type of industry based on pure gases derived from air. The atmosphere consists mainly of oxygen and nitrogen having boiling points of -183 ° C and -196 ° C, respectively. Thus, the two gases could be separated by extremely strong cooling.
In 1895, Linde managed to extract pure oxygen from distilled air. Four years later, at the World Exhibition in Paris, he introduced the first machine for commercial production of oxygen and nitrogen through the same technology. Steel bottles with the pure oxygen under high pressure immediately found a market in the iron and steel industry and hospitals as well. There is not only oxygen and nitrogen in the air but also 1% argon – a gas considered commercially worthless at times. But later, argon was used in fluorescent tubes, for welding and as protective gas in the metal and semiconductor industry. The Linde Group is the world’s largest industrial gas company today.
Industrial refrigerators in daily life
Because of their size and price, industrial refrigerators were quite useless for the household usage, which was otherwise a promising market for new refrigeration technologies. By 1910, the people in Europe and North America had been using the same cooling method for 100 years earlier. But about ten years later, American housewives could buy the first electric refrigerators with water-cooled compressor either built into the closet or placed in an adjoining room. The devices were clumsy, the price was high and the sales volume was low. In 1923, there were only 20,000 refrigerators in the whole country.
The first type of refrigerator that was seriously popular to American people was introduced by General Electric in 1927. The model had the compressor standing on top of the cabinet and used either sulfur dioxide or methyl (C 2 H 4 O 2) as refrigerant. Both were toxic and harmful substances. This first generation of refrigerators worked well but had some problems like gas leaking. Nevertheless, General Electric sold over a million refrigerators in the United States in five years.
1 million compression refrigerators in 1936
Compression refrigerators were not the only choice on the market. The alternative was the absorption technique that Carré had already used in 1859. Baltzar von Platen (1898-1984) and Carl Munters (1897-1989),two students at the Technical High School in Stockholm, developed a refrigerator without an electrically powered compressor, using their knowledge of thermodynamics to construct a refrigerator based on hydrogen and ammonia. Their project was bought by Electrolux in 1925, the company which had just started as a vacuum cleaner manufacturer. As it did not really work, Electrolux invested in the more successful one; compression technique. The company managed to produce 1 million refrigerator in 1936.
Smaller and cheaper refrigerators with freon
An important reason for the breakthrough of the refrigerator in the 1930s was the invention of the refrigerant freon. Freon was safer and had far better properties than previous substances such as sulfur dioxide, ammonia and methyl chloride. With the new refrigerant, the refrigerators became smaller and cheaper, and sales were increased with this smarter design and massive advertising campaigns.
As a result, over half of US people had refrigerators in the late 1930s. With the inclusion of the refrigerator in the homes, the consumption pattern also changed, as it was now possible to buy large amounts of food.
Freon is the trade name of a class of fluorine compounds, which was synthesized by researchers at General Motors and was produced by the chemical group Du Pont from 1930. Examples are trichlorofluoromethane (CFCl 3 ) and difluorodichloromethane (CF 2 Cl 2 ).
Freon was a huge success, but not completely seamless
Freon was a huge success, but although it was non-toxic and odorless, it proved to be harmful in the long term.
British researchers had discovered a large hole in the layer of ozone (the unstable oxygen molecule O3 ) which protects the Earth from the Sun’s ultraviolet radiation in the upper atmosphere. It soon became apparent that releases of freon and similar gases was dangerous for ozone layer. High in the atmosphere, their chlorine atoms will contribute to the conversion of ozone into regular oxygen (O2 ). Hence, Freon suddenly became a notorious rather than famous substance, and in 1996, the United Nations recommended completely prohibiting its use.
In major industrialized countries, freon is now being phased out and replaced by other substances that are less harmful to the ozone layer. It is still a research area, and a common standard for future refrigerants has not yet been found.
One thing, however, is certain: the refrigerator has come to stay – harmful environmental effects or not. A world without refrigerators and freezers was a reality in our great-grandfather’s generation, but today it’s almost unthinkable.