The refrigerator is such an important component of modern life that it is hard to imagine what the world was like without it. Before mechanical refrigeration systems were introduced, people had to cool their food using earthern pots, ice and snow, either found locally or brought down from the mountains.
The first cellars for keeping food cold and fresh were holes that were dug into the ground and lined with wood or straw and packed with snow and ice. This was the only means of refrigeration throughout most of human history.
What Is Refrigeration?
Refrigeration is the process of creating cooling conditions by removing heat. It is mostly used to preserve food and other perishable items, preventing foodborne illnesses. It works because bacteria growth is slowed at lower temperatures. The advent of modern refrigerators changed everything, eliminating the need for ice houses and other crude means of keeping food cool.
The Early Refrigerators
The first known artificial form of refrigeration was demonstrated by William Cullen at the University of Glasgow in 1748. Cullen’s invention, though ingenious, was not used for any practical purpose. In 1805, an American inventor, Oliver Evans, designed a blueprint the first refrigeration machine.
But it wasn’t until 1834 that the first practical refrigerating machine was built by Jacob Perkins. The refrigerator created cool temperatures using a vapour compression cycle.
Ten years later, an American physician named John Gorrie built a refrigerator based on Oliver Evans’ design. Gorrie used the device to cool the air for his yellow fever patients. In 1876, German engineer Carl von Linden patented the process of liquefying gas that has become part of basic refrigeration technology.
The Modern Refrigerator
Refrigerators from the late 1800s until 1929 used toxic gases such as ammonia, methyl chloride, and sulfur dioxide as refrigerants. This led to several fatal accidents in the 1920s, the result of methyl chloride leaking out of refrigerators. In response, three American corporations launched collaborative research to develop a less dangerous method of refrigeration, which led to the discovery of Freon.
In just a few years, compressor refrigerators using Freon would become the standard for almost all home kitchens. Only decades later would people realize that these chlorofluorocarbons endanger the ozone layer of the entire planet.
As of 2018, compressor refrigerators were still the most common, though some countries have made efforts to phase out the use of chlorofluorocarbons. Some machines now use alternative refrigerants that are not as harmful to the atmosphere.
There even exist refrigerators that operate using solar, magnetic, and acoustic energy.
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