Imagine a modern home without a refrigerator? Well, it’s hard to even think what we would do without refrigeration. Modern cities in developed countries depend heavily on refrigeration to keep perishable food items fresh and safe for daily consumption. The technique of refrigeration has impacted agriculture, industry and lifestyles across centuries evolving from ice harvesting to temperature controlled rail cars.
Refrigeration is the name given to the process that ‘removes heat from one location to another’ creating a cool or cold environment that has many applications like household refrigerators, air conditioning systems, cryogenic facilities and industrial freezer units.
The idea of cooling beverages has its origin in the ancient Chinese and Roman empires. Seasonal harvesting of snow and ice is a practice dated prior to 1000 B.C. according to a collection of Chinese lyrics from the period known as the Shih dynasty. The next mention of ice harvesting is in the time of the Jews and is mentioned in the book of Proverbs in the Bible. Other civilizations such as the Egyptians, Greeks and Romans made use of large snow pits lined with tree branches and chaff to cool beverages and keep fruit cool. But it was not until the Persian culture when the usage of an ice pit called Yakhchal is mentioned; this may be the precursor to cold storage of food for preservation.
In the early 1800s, ice became a mass-market commodity with a large majority of people using ice boxes to store dairy products, fish, fruits, meat and vegetables, thus paving the way for the acceptance of refrigeration technology.
Refrigeration – the timeline
William Cullen, a Scottish professor was the first to examine the idea of artificial refrigeration by creating a partial vacuum over a container of diethyl ether that absorbed heat from the surrounding air. This was in 1755 but the experiment had no practical application at that time.
In 1758, professors Benjamin Franklin and John Hadley investigated the principle of evaporation as a means of rapidly cooling an object by conducting an experiment at Cambridge University.
In the year 1820, renowned British Scientist Michael Faraday used high pressures and low temperatures to liquefy ammonia and other gases.
American scientist Jacob Perkins working in Great Britain in 1834, assembled the first ever closed-cycle vapor compression refrigeration system. Although the prototype, not patented, was the first known system to function successfully, it did not have any commercial success.
American physician John Gorrie made a similar attempt in 1842 but again it was a commercial failure.
The first patented, practical vapor compression refrigeration system using alcohol, ether or ammonia came in 1856 built by James Harrison.
In 1860, Ferdinand Carre of France patented his gas absorption refrigeration system design referred to as “aqua ammonia”, the process of using gaseous ammonia dissolved in water.
Meanwhile, an engineering professor at the Technological University Munich in Germany had been working on an improved method of liquefying gases. In 1876 he patented this new process which was made possible by using gases such as ammonia, sulphur dioxide and methyl chloride as ‘refrigerants’, a practice that began to be widely used until the late 1920s.
A refrigerant is a substance or chemical used in a heat cycle, as in the case of refrigeration, to convert liquid into gas.
By the turn of the 19th century, refrigeration came to play a vital role in the food distribution industry first through natural ice and then on manufactured ice. Many food and meat packing houses in America adopted ammonia-cycle refrigeration units for their storage facilities.
With the idea of artificial refrigeration a huge success, came the thought of refrigeration for household purposes. The limitations were largely on account of size as they were designed for installation on lorries, truck and storage houses and the safety factor in case of fire accidents where toxic gases leaked or exploded.
Refrigeration for the home
In 1911, General Electric (GE) became the first company to overcome the challenges of meeting refrigeration needs for the home. GE released a household unit powered by gas that eliminated the need for a motor and considerably decreased the size of the unit. However, the idea of a gas-powered unit did not go down well with electric customers of GE so an electric model framework was set into operation.
In 1927, Monitor Top, the world’s first ever refrigerator to run on electricity was released. The idea created waves with many other companies hitching their bandwagon in the run-up to improve upon this new invention.
One of GE’s main competitors, Frigidaire entered the fray in 1930, synthesizing Freon as a refrigerant. This was a breakthrough invention that enabled the development of cheaper, lighter and smaller refrigerators for home use. At that time the use of Chlorofluorocarbon (CFC) was considered to be less harmful than the more commonly used refrigerants like ammonia, methyl chloride and sulphur dioxide. The intent was to provide safer home equipment at affordable prices.
Nowadays, home refrigerators have become stylized home appliances with a variety of designs, colors and sizes with varying temperature control functions to cater to the needs of small, medium and large families.
In the 1970s when the world became aware of environmental concerns and global warming, these CFC compounds were found to be reacting with the protective atmospheric ozone layer bringing down the use of CFCs as a refrigerant as laid down in the 1987 Montreal Protocol. Today, manufacturers have embraced the idea of using eco-friendly refrigerants like hydrocarbons as a means to combat global warming and reduce the impact of greenhouse gases.