Refrigeration cycle: Types, Differences, And What to Choose
Refrigeration system and basic refrigeration cycle
In this article refrigeration cycle, we will discuss cooling and defrosting systems used in modern fridges, namely available types and their features.
No Frost
The most effective yet inexpensive cooling/defrosting system. The most budget-friendly models tend to use Full No Frost configuration (i.e. both in freezer and refrigerator compartments).
The unit comprising evaporators and heating elements is installed between the two compartments, while fans direct the cool air to the fridge and freezer compartments.
Shortly after, frost deposits melt away under the heat produced by the system. It actually means that No Frost fridges still have some frost, but it’s not visible.
As I mentioned before, the key advantages of such models are effective cooling/freezing and low price. However, Full No Frost can be also found in expensive fridges.
Usually, they are two-door Side-by-Side models that are extremely hard to cool down with a static system due to their large volume.
Regular-shaped Full No Frost fridges also can be expensive if they use a dual-loop system with 2 separate evaporator units.
In this case, the major downside is the skinning of products caused by the constant airflow from the fans.
Nevertheless, this negative effect is related only to fresh products kept in a fridge compartment without packing.
No Frost doesn’t actually have any significant downsides in the freezer — you won’t need to defrost it regularly, and products are naturally stored in packing.
Hybrid Cooling
The dual effect of No Frost on different fridge compartments has resulted in a more practical hybrid cooling system: No Frost in the freezer and a static system in the cooling compartment.
The static cooling system is also known as a "wet wall" — this name follows the operation principle: the evaporator is installed on the back wall of the compartment, so when the compressor is off, frost deposits start to melt and droplets trickle down the wall.
Such compartments will allow your package-free products to remain fresh and juicy longer. However, keep in mind one thing: do not leave the food (especially fruit, vegetables, and greens) touching the back wall, otherwise it may lead to a clogged-up drain or growth of bad-smelling bacteria.
Dynamic Cooling
In some cases, "wet wall" cooling compartments are equipped with a fan. While it helps to achieve smoother distribution of temperature in the compartment and increase fridge power efficiency, it deprives the system of its major advantage, namely avoiding product skinning.
The difference is not critical, but if you’re buying a hybrid fridge, I would recommend opting for a classic static cooling system.
Non-uniform frost distribution can be solved by correct product positioning — in this case, the feature can be considered as an advantage.
Static Cooling in Freezers
As a rule, the static cooling system in freezers is used only together with the static cooling in the fridge (i.e. there are no reverse hybrids).
Spacious freezers use a multi-level system when a few evaporators are installed inside and used as shelves.
German manufacturers (Bosch and Liebherr) sometimes utilize a modified static cooling system – Low Frost. It doesn’t have much in common with No Frost, apart from no thick blankets of ice.
This is achieved by specific positioning of evaporators: they are installed all over the compartment area behind the walls (except for the door).
As a result, there are no rapid temperature changes, the frost takes more time to build up (and less time to defrost), and it slightly increases freezing efficiency.
Bottom Line
Hybrid cooling systems look more beneficial if we consider food storage quality and utility. However, it’s not the only correct decision, even for an unlimited budget.
The skinning problem of Full No Frost fridges can be solved by a couple of closed containers (they are usually called "fresh zones", but it’s not actually correct, because a good FZ has a separate cooling loop with temperature and humidity adjustment) and keeping products packed.
Full No Frost is also a great solution for high-humidity areas. However, if you’re not planning to buy a Side-by-Side model, FNF will be your only available option.
Static systems in freezers are not considered as a separate feature, because the core reason to buy such fridges is their brand and trust in durability.