Artificial refrigeration: This is how the technology originated and evolved through time
It’s impossible to imagine a life without refrigerators, isn’t it? Ever wondered how food was stored before refrigerators were discovered? People had to cool or preserve their food using ice or snow! The earliest cellars to keep food cold and fresh were tunnels dug inside the earth, lined with wood or straw and filled with snow. Holes were dug in the ground to store milk in pots. However, everything changed when modern freezers were invented. They replaced the necessity for ice storage rooms and other primitive methods of food cooling.
So, how do refrigerators keep our food cold? It acts by evaporating a special liquid (a refrigerant). The heat required for evaporation is absorbed from an enclosed area or material, reducing the temperature of the area. So, the refrigerant in the fridge evaporates by absorbing the heat from the food and the surroundings, keeping the insides cool! Now you know how refrigeration works, let’s find out how the technology was invented.
Artificial refrigeration develops as concept
It was Scottish physician and professor, William Cullen who demonstrated the first case of artificial refrigeration. In 1748, he observed and tested the cooling effect after rapidly evaporating a liquid into gas. But he didn’t put this process to practical use. So, he wasn’t the one to use this concept for refrigeration. In 1805, an American inventor and engineer, Oliver Evans, created a blueprint for the first refrigeration machine. However, he didn’t build it.
The first vapor compression system was built in 1834 by an American inventor and mechanical engineer, Jacob Perkins. In this system, a circulating liquid refrigerant was used to absorb and remove heat from the area that had to be cooled. So far, a compressor system and a blueprint were built but the first electric refrigerator came much later.
The advent of home refrigerators
Not one, but many scientists and researchers contributed to the development of refrigerators that we use today. However, we should especially thank one of them for the fridges that keep our food and ice creams cool at home Fred W. Wolf. This American theoretical physicist created the first home electric refrigerator in 1913 which included a refrigeration unit on top of an icebox.
Actually, around this time, necessity of refrigeration increased as people started moving away into the cities, far away from fresh food sources. Hence, the shelf life of food had to be prolonged. However, the mass production of residential refrigerators can’t be credited to Wolf. It all started when American industrialist and founder of the automobile manufacturing company General Motors, William C. Durant, unveiled the first house refrigerator with a self-contained compressor in 1918. The compressor is the ‘heart’ of a refrigerator. It moves the refrigerant across the whole system.
Toxic gases as refrigerants
During the late 1800s and through the 1920s, hazardous gases such as ammonia, methyl chloride and sulphur dioxide were used as refrigerants. But methyl chloride leakage from refrigerators resulted in several deadly mishaps during this time. To find a solution, three US businesses began working on research projects to create a less hazardous refrigeration technique. In 1928, two American engineers, Thomas Midgley Jr. and Charles Franklin Kettering, created the freon. This refers to various chlorofluorocarbons (CFCs), which replaced the earlier refrigerants in the industry.
Are there safer alternatives?
Freon-powered compressor refrigerators quickly replaced conventional refrigerators in practically all homes. Decades later, people realised how dangerous these CFCs are for the ozone layer (CFCs can deplete the ozone layer!). Even though some nations have taken steps to phase out the usage of CFCs, compressor refrigerators that use freon are still being used.
Are there any alternatives? HFO-1234yf, an organic compound, is less environmentally hazardous and currently used in some machines. Refrigerators that use solar, magnetic or sonic energy are also available but not very popular. A greener refrigerator could be constructed in the future!