How a Freezer Works


By : Steven Hanger - Web Design Leader / CAD Leader / Team Leader,
Rex Bianchi - Lead of Research / Disassembler / Web Design,
and Ethan Pierce - CAD Worker / Lead Disassembler

History of the Freezer

Here is a brief overview of the history of freezers (and refrigerators)
  • In 19th century England the predecessor of artificial refrigeration devices, the icebox, was born. This used natural ice to keep food cool.
  • Many people had major research that contributed to the science of mechanical refrigeration devices such as Michael Farday who created liquefied ammonia, the first refrigerant
  • Soon after electric refrigeration devices were released in the 1920s sulfur-dioxide was replaced by R12 as the most commonly used coolant.
  • In the 70s and 80s refrigeration devices were made more environmentally friendly, being more energy-efficient, and having R12 (a CFC) replaced by R134a (a HFC)

    • How A Freezer Works Video

    Components of a Freezer

    Name Picture Purpose
    Compresser Compresses vaporized refrigerant after refrigerant cycle
    Condenser Coils Condenses refrigerant into liquid
    Evaportator Coils Located inside the freezer, refrigererant passes through as it evaporates
    Expansion device Causes refrigerant to rapidly evaporate as it enters a low pressure zone
    Refrigerant A material with a low boiling point; wicks heat away from inside the freezer

    Freezers work using refrigerant that absorbs heat when it is evaporated. Refrigerant is heated and pressurized by a compressor.
    This hot gas then passes through a condenser, which condenses it into a liquid.
    Then this liquid passes through an expansion device, which causes this liquid to evaporate and cool down, this cool gas is then passed through the evaporator coils (located inside the freezer).
    While in the evaporator coils, the refrigerant absorbs the heat out of the freezer, making it cold again then goes back into the compressor, and the cycle repeats itself.

    3D Model of a Freezer

    The Science behind Refrigerant


    How Refrigerant Works

    So, what is the magic material, refrigerant, that keeps our food ice cold. Well, refrigerant really isn't that complicated. All refrigerant is is a material with a extremely low boiling point. R-134a, the refrigerant we are currently using in refrigerators, has a boiling point of -15.34 degrees Farienheight. However, this boiling point is increased significantly when pressure is applied, in a freezers case the compresser. This refrigerant absorbs the heat of the freezer because when it boils after it loses pressure (beacause the boiling point is reduced) from passing through the expansion device and absorbs heat in the freezer.

    R12 and the Ozone Layer

    I said in the history segment that there used to be another coolant, R-12. Why was that replaced? Well, R-12 was a CFC (chlorofluorocarbon) which were found to destroy the ozone. R-12 was actually the one of the worst CFCs because it stayed in the ozone for an extended period of time, destroying ozone molecules, and preventing new ones from forming with a series of chemical reactions.

    Different Types of Refrigerant