In
refrigerator
A refrigerator, colloquially fridge, is a commercial and home appliance consisting of a thermally insulated compartment and a heat pump (mechanical, electronic or chemical) that transfers heat from its inside to its external environment so th ...
s, defrosting (or thawing) is the removal of
frost
Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a g ...
and
ice.
A defrosting procedure is generally performed periodically on refrigerators and
freezer
A refrigerator, colloquially fridge, is a commercial and home appliance consisting of a thermally insulated compartment and a heat pump (mechanical, electronic or chemical) that transfers heat from its inside to its external environment so th ...
s to maintain their operating efficiency. Over time, as the door is opened and closed, letting in new air,
water vapour from the air condenses on the cooling elements within the cabinet.
Types of frost (in various environments) include crystalline frost (
hoar frost
Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a ga ...
or radiation frost) from
deposition
Deposition may refer to:
* Deposition (law), taking testimony outside of court
* Deposition (politics), the removal of a person of authority from political power
* Deposition (university), a widespread initiation ritual for new students practiced f ...
of water vapor from air of low humidity,
white frost
Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a ga ...
in humid conditions,
window frost
Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a ga ...
on glass surfaces,
advection frost
Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a ga ...
from cold wind over cold surfaces,
black frost
Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a ga ...
without visible ice at low temperatures and very low humidity, and
rime
Rime may refer to:
*Rime ice, ice that forms when water droplets in fog freeze to the outer surfaces of objects, such as trees
Rime is also an alternative spelling of "rhyme" as a noun:
*Syllable rime, term used in the study of phonology in ling ...
under
supercooled
Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid or a gas below its melting point without it becoming a solid. It achieves this in the absence of a seed crystal or nucleus around which a crysta ...
wet conditions.
The resulting ice inhibits heat transfer out of the cabinet increasing running costs. Furthermore, as the ice builds up it takes increasing space from within the cabinet - reducing the space available for food storage.
Many newer units employ
automatic defrosting (often called "frost-free" or "no frost") and do not require manual defrosting in normal use. Although, in some cases, users of Frost Free fridge/freezers have noted ice blocking the vent that allows air into the refrigerator compartment.
References
{{ref-list
Cooling technology