We all must have seen Refrigerator at homes as essential household appliances now-a-days. Also we know very well it is used for preservation of food but have we ever think how people used to store or preserve food centuries ago when the refrigerator was not invented. How the need for its invention become necessary and what were the evolutions came in its invention journey. Let’s have a look.
Food preservation was not always so easy like today with Refrigerators because Bacteria are present in all food and at room temperature they multiply rapidly, making food inedible and even dangerous. Centuries ago, Most people rely on canning, pickling and salting their food to preserve it. Also, bacterial activity slows dramatically in cold temperatures. At freezing point or below, it stops. So keeping food cold can maintain its freshness for days when it might otherwise last only hours. Freezing can preserve it for months or years.
People used to gather ice from streams and ponds and store it year round underground to use during summers to keep things chilly.
According to the Association of Home Appliance Manufacturers, middle step between storing ice underground and modern refrigeration was the icebox. Wooden ice boxes lined with tin or zinc, filled with sawdust were used to store ice preventing it from melting.
Thomas Jefferson's employed the process of maintaining the ice house at the Monticello Estate. Every winter, he brought in more than 60 wagonloads of ice from the nearby Rivanna River to keep his ice house filled.
There are proofs indicating that the Egyptians, Chinese and Indians used ice in food preservation.
In 1626, Sir Francis Bacon was also testing the idea that cooling meat could be used to preserve it but his chilly experiment caused him to develop pneumonia, from which he died on Easter Day, April 9, 1626.
The first known artificial refrigeration method was demonstrated by William Cullen at the University of Glasgow in 1748. However, he did not use his discovery for any practical purpose.
Benjamin Franklin put the first step toward the invention of the refrigerator. In 1758, he along with chemist John Hadley experimented with the effects of evaporation on temperature. By repeatedly swabbing ether on a thermometer and allowing it to evaporate, the pair was able to drop the thermometer's temperature to well below freezing point.
In 1805, an American inventor, Oliver Evans, worked on the principles developed by Franklin and designed the first refrigeration machine.
In Refrigeration machine, a "refrigerant" gas is forced, by compression, to condense into liquid and then evaporate back into gas. As it does so it draws heat from inside the machine and makes it cooler. This cycle repeats again and again, so the fridge is kept constantly cold.
In Philadelphia, Evans became friends with a young inventor called Jacob Perkins. Perkins took Evans' design and started modifying it, received a patent on his own design in 1834. He then persuaded a man named John Hague to construct the machine, and the refrigerator was born. It used ether in a vapor compression cycle.
An American physician, John Gorrie, built a refrigerator based on Oliver Evans' design in 1844 to make ice to cool the air for his yellow fever patients. He also pioneered air conditioning at the same time, since his idea was to blow air across the ice-making machine to cool hospital patients suffering from malaria in Florida.
In 1856 another American, Alexander Twinning, began selling a fridge based on compressing gas.
In 1859, France’s Ferdinand Carre created a more advanced system that used ammonia as a coolant. The earlier vapor-compression machines used air. The ammonia worked well, but was toxic if it leaked.
Fred W. Wolf invented DOMELRE, an air-cooled refrigeration unit. It was the first commercially viable electric refrigerator in the United States. It was mounted on top of an icebox.
In 1915, Alfred Mellowes designed an electric refrigeration unit that was self-contained; the compressor was in the bottom of the cabinet. Guardian Refrigerator Company started manufacturing and selling Mellowes’ version of the refrigerator in 1916.
W.C. Durant, who was president of General Motors, purchased the Guardian Refrigerator Company privately, and the business was renamed Frigidaire. The first Frigidaire refrigerator was completed in September 1918 in Detroit.
Continued improvements in the production of refrigerator, along with organizational changes in the company resulted in a better product with reduced price. Frigidaire eventually added ice cream cabinets to models in 1923, soda fountain equipment in 1924, and water and milk coolers in 1927. By 1929, 1 million refrigerators had been produced, a marked improvement from the early years.
It still took another 40 years, around the end of World War I, before fridges were being mass produced and cheap enough for ordinary consumers. The first combined fridge-freezer came along in the US around 20 years later in 1939.
Refrigerators from the late 1800s until 1929 used the toxic gases ammonia (NH3), methyl chloride (CH3Cl), and sulfur dioxide (SO2) as refrigerants. Several fatal accidents occurred in the 1920s when methyl chloride leaked out of refrigerators.
Three American corporations launched collaborative research to develop a less dangerous method of refrigeration; their efforts lead to the discovery of Freon.
In just a few years, compressor refrigerators using Freon would became the standard for almost all home kitchens. But Freon emits chlorofluorocarbons which are very harmful for the ozone layer in our atmosphere.
Research are being going on for a new alternative in place of Freon to design an eco-friendly Refrigerator. Hope we will see it soon.