Concept

As time passes, the water vapor in the air in a refrigerator condenses on the cooling coils as frost. In course of time, it becomes a thick layer of ice. This layer has an insulating effect and decreases cooling efficiency. Previously, this layer was removed by turning the refrigerator off and using hot water manually. However, in frost free refrigeration, a heater and thermostat are fitted near the cooling coils. For some time, the cooling is switched off and the heater is turned on till the temperature around the coils exceeds the freezing point of water. After this, usual cooling is started again. Any frost that has accumulated around the coils melts off. The melted water is collected in a gulley and then through a small pipe is passed to the top of the compressor. The residual heat generated by the power of the compressor evaporates the water.

Ice

During power failure, a warning displaying the temperature is used to alert the user. Information is also given regarding the condition of the frozen food and whether it contains any harmful bacteria. A status indicator notifies the user the time to change the water filter. An in-door ice caddy is removable and prevents ice-maker clogging. It relocates the ice-maker storage to the freezer door and 60 liters of freezer space is saved. Air from the freezer compartment is passed to the refrigerator door to cool the juice or milk stored in the door shelf.

Freezer advancement

Previously, freezer units were surrounded by ice crystals. This was a result of opening of doors of the freezer. Humidity is passed into the freezer compartment during the opening of the doors. Due to this growth of frost, it became necessary to have periodic melting of these units to avoid the decrease of efficiency. In the 1950s, there were certain advancements in frost free refrigeration technology. These avoided the need of thawing the units. Moreover, previously, the freezer compartments were placed inside the large refrigerators. These had to be accessed by initially opening the refrigerator door and then the freezer door. In the 1960s, devices consisting of entirely separate freezer compartment were manufactured. By 1965, this became the industry standard. Further, automatic ice units and self compartmentalized freezing units were devised.