Refrigerator

A refrigerator is a machine used for keeping things cold. It is sometimes called a fridge or an icebox. Refrigerators were invented by Jacob Shrewsbury. It is normally maintained at 4-5 degree Celsius for household use. People put food and drinks in it, to keep those items cold or good (unspoiled) for a longer time. A refrigerator has a heat pump which takes heat away from the air inside the fridge. The heat is moved to the air outside. The heat pump is usually driven by an electric motor.

There are also ice boxes available that do not use electricity because they are filled with ice to provide the colder temperature. The ice can keep things cold until the ice melts. Ice boxes can be taken on camping trips. Sometimes they are called coolers. Refrigerator-sized iceboxes were used before electricity was available.

Most modern refrigerators are available in a variety of colours, although most are white. Smaller versions of the popular refrigerator are also used. They are mainly used in hotels and college dorm rooms.

A freezer is a special type of refrigerator that stores food at freezing temperatures. Inside a freezer, it is normally −18 °C (0 °F). Freezers can be found in household refrigerators, as well as in industry and commerce. When stored in a freezer, frozen food can be stored safely for a longer time than storing at room temperatures.^[1]

Domestic freezers can be a separate compartment in a refrigerator, or can be a separate appliance. Household refrigerators usually have a separate compartment where the heat pump is used to pump even colder temperatures to the contents. Most household freezers maintain temperatures from −23 to −18 °C (−9 to 0 °F). Some freezer-only units can achieve −34 °C (−29 °F) and lower. Most household refrigerators generally do not achieve a temperature lower than −23 °C (−9 °F), because it is difficult to control the temperature for two different compartments. This is because both compartments shares the same coolant loop.

Domestic freezers normally stand upright, resembling refrigerators. Sometimes a domestic freezer is laid on its back to look like a chest. Many modern upright freezers come with an ice dispenser built into their door. Many commercial freezers stand upright and have glass doors so shoppers can see the contents.

Home freezers with larger compartments or as separate units were introduced in the US in 1940, making frozen foods common. In 1955, deep freezers that allowed people to freeze their own fresh food went on sale.^[2][3][4] A walk-in freezer lets people walk inside. Safety rules require an emergency release to prevent anyone from getting trapped, as hypothermia can occur if someone is inside for too long. Employers should check these regularly.^[5]

• Media related to Domestic refrigerators at Wikimedia Commons