Physics

How do refrigerators work?


There is evidence that humans, from the earliest times, have noticed that simply cooling food could conserve them for a longer time. Most likely, the appropriations of territories were responsible for the dissemination of this knowledge to civilizations.

However, it was not until the nineteenth century that Jacob Perkins, an English inventor, developed a compressor capable of solidifying water, artificially producing ice. And, of course, this discovery has enabled some industries, such as breweries, to thrive. In addition, the commercial sector was also greatly favored as it became possible to ship the products to several distant countries.

As early as the twentieth century, Willis Carrier, an American, installed the first air conditioner in a New York press, which was able to control the humidity of the environment and cool it.

The first household refrigerators (better known as refrigerators) appeared in the United States in the early 1920s, becoming popular very quickly. In Brazil today, it is estimated that more than 80% of households have a refrigerator.

Components

Basically, a refrigerator is made up of the following elements:

  • Refrigerant: which must have low vaporization pressure and high condensation pressure, as is the case with freon - the most commonly used refrigerant.
  • Compressor: It functions as a suction pump that draws fluid from the branch of the pipe that precedes it (reducing the pressure) and injects this fluid into the branch of the pipe that follows it (increasing the pressure).
  • Condenser: It is an external coil, located on the back of the refrigerator, in which the vapor liquefies, and which is responsible for releasing heat to the environment.
  • Capillary tube: It is responsible for decreasing the vapor pressure of the fluid.
  • Evaporator: It consists of a coil-shaped tube attached to the freezer. To pass into the gaseous state, the fluid absorbs energy in the form of heat from the freezer and, upon leaving the evaporator, reaches the compressor, restarting the cycle.
  • Freezer: It is located at the top of the refrigerator to facilitate the formation of internal convection currents, allowing the low temperature air of the freezer and its surroundings to be mixed with the higher temperature air of the other parts.