The inside of a home refrigerator containing a large variety of everyday food items.
Newer refrigerators may include:
· Automatic defrosting;
· A power failure warning, alerting the user by flashing a temperature display. The maximum temperature reached during the power failure may be displayed, along with information on whether the frozen food has defrosted or may contain harmful bacteria;
· Chilled water and ice available from an in-door station, so that the door need not be opened;
Water and ice dispensing became available in the 1970s. Also, some refrigerators have ice makers built-in so, the user doesn't have to Edit] Features use ice trays. Some refrigerators have water chillers and water filtration systems.
· Cabinet rollers that allow the refrigerator to be easily rolled around for easier cleaning;
· Adjustable shelves and trays which can be repositioned to suit the user;
· A status indicator to notify the user when it is time to change the water filter;
· An in-door ice caddy, which relocates the ice-maker storage to the freezer door and saves approximately 60 litres (2 cu ft) of usable freezer space. It is also removable, and helps to prevent ice-maker clogging;
· A cooling zone in the refrigerator door shelves. Air from the Edit] Features freezer section is diverted to the refrigerator door, to cool milk or juice stored in the door shelf.
Early freezer units accumulated ice crystals around the freezing units. This was a result of humidity introduced into the units when the doors to the freezer were opened condensing on the cold parts, then freezing. This frost buildup required periodic thawing ("defrosting") of the units to maintain their efficiency. Manual Defrost (referred to as Cyclic) units are still available. Advances in automatic defrosting eliminating the thawing task were introduced in the 1950s, but are not universal, due to energy performance Edit] Features and cost. These units utilized a counter, that only defrosted the freezer compartment (Freezer Chest) when a specific number of door openings had been made. The units were just a small timer combined with an electrical heater wire which heated the freezer's walls for a short amount of time to remove all traces of frost/frosting. Also, early units featured freezer compartments located within the larger refrigerator, and accessed by opening the refrigerator door, and then the smaller internal freezer door; units featuring an entirely separate freezer compartment were introduced in the early 1960s, becoming the industry Edit] Features standard by the middle of that decade. These older freezer compartments were the main cooling body of the refrigerator, and only maintained a temperature of around -6°C, which is suitable for keeping food for a week.
Later advances included automatic ice units and self compartmentalized freezing units.
An increasingly important environmental concern is the disposal of old refrigerators – initially because of the Freon coolant damaging the ozone layer, but as the older generation of refrigerators disappears it is the destruction of CFC-bearing insulation which causes concern. Modern refrigerators usually use a refrigerant called HFC-134a (1,1,1,2-Tetrafluoroethane), which Edit] Features does not deplete the ozone layer, instead of Freon. A R-134a is now becoming very uncommon in Europe. Instead, newer refrigerants are being used instead. The main refrigerant now used is R-600a, or isobutane. This refrigerant is naturally occurring and therefore has a smaller effect on the atmosphere, if released. There have been some reports of refrigerators exploding, if the refrigerant leaks and comes into contact with a spark.
Disposal of discarded refrigerators is regulated, often mandating the removal of doors; children playing hide-and-seek have been asphyxiated while hiding inside discarded refrigerators, particularly older models Edit] Features with latching doors. Since August 2, 1956, under U.S. federal law, refrigerator doors are no longer permitted to lock from the inside. More modern units use a magnetic door gasket which holds the door sealed but can be pushed open from the inside. This gasket was invented by Herman C. Ells Sr.