- Certain bibcocks (sillcocks) are also known as frost frees.
A frost free (also called Auto-defrost or no-frost) refrigerator or freezer incorporates technology to keep the unit from icing up.
The mechanism on a refrigerator involves letting the cooling element heat up for a short period, melting any ice
that has formed upon it and having it drain through a collecting duct at the back of the unit.
Inside the freezer, dry air is circulated around the cabinet using fans (this is why such kind of appliances are also called "dynamic", whereas non-frost free ones are called "static").
Instead of the traditional cooling elements assembled within all the freezer liner, those of a frost-free system are compact and separated from the main cabinet space, allowing them to be heated for short periods to dispose of any ice forming.
While this technique was originally and is mostly applied to freezer compartments, it can also be used for fridge compartments.
A combined fridge/freezer which applies the frost free system to the freezer compartment only is usually called "partial
frost free", while one which also applies it to the fridge compartment is called "total
frost free". The latter features an air connection between the two compartments, with the air passage to the fridge compartment regulated by a damper. In such a way, a controlled minor part of the dry and fresh air coming from the dynamic cooling element located within the freezer can reach the refrigerator.
Some newer fridge/freezer models have built-in electronics that monitor how many times each door is opened and could also average the door open time which will automatically adjust defrost scheduling, therefore optimizing power dissipation.
Advantages of frost free
- No need to manually defrost the ice buildup
- Food packaging is easier to see because it's clear of frost
- Most frozen foods don't stick together
- Smells are limited, especially in total frost free appliances, since the air is constantly circulating
Disadvantages of frost free
- The system is more expensive to run due to higher power consumption
- A safety device is required to be connected with the heating element, due to the high instant-power values that can be reached
- The temperature of the freezer contents rises during the defrosting cycles
- On hot humid days condensation will sometimes form around the refrigerator doors
In laboratories, frost-free freezers must not be used to store certain delicate reagents such as enzymes, because the temperature cycling can degrade them. In addition, water can sublimate out of containers that do not have a very tight seal, altering the concentration of the reagents.