Advantages and disadvantages of static and dynamic cooling in Orest refrigerated tables.
At the beginning let’s review a static cooling system because it was used in the most number of early models of household and industrial refrigerators; as it is seen from the title a static cooling system implies the absence of air circulation inside the refrigeration compartment (air immobility).
Notwithstanding in this case statics is a conditional notion, although air is moved very slowly, but it is moved: warm air inside the refrigeration compartment ascends up, while cold air descends to the lower wall of the refrigeration compartment (natural air convection is performed).
As a result of such air movement individual zones with temperature difference in 5-6 degrees Celsius occur in the refrigerated table that will enable to choose the necessary temperature zone for different types of products. In this case moisture is not evaporated, but remains inside the refrigeration compartment. When the compressor is switched off moisture is condensed on the back wall of the refrigerator and drips in the special evaporator. Just because of dripping such cooling system is often called as “drip cooling system”.
This system is operated on a principle of perpetual cycles: cooling – freezing – defrosting; refrigerated tables with static cooling system are equipped with hand heat controllers used for optimization of duration and frequency of these cycles. For defrosting purpose one shall switch it off and open doors. Defrosted and dripping to the tray water shall be poured out, the refrigeration compartment shall be wiped dry and ventilated. Recommended defrosting frequency of the refrigerated table is stated in technical specification of each certain model.
One should specify that the refrigerated table with static cooling is cheaper than the table with dynamic cooling due to easier construct.
One more significant advantage of refrigerated tables with static cooling is that there is no necessity to store products in a package because crusting effect of products is absent.
As for dynamic cooling, its main feature is actually absence of frost on walls of the refrigeration compartment.
Due to this feature dynamic cooling system is often called as “No Frost” (in translation from English it means “without frost”).
This result is achieved by means of air circulation inside the refrigerated table; the air circulation is enforced by special inbuilt fans. The evaporator is located behind the back wall of the refrigerated table; this evaporator ensures cooling of the back wall to the set temperature. With the help of fans a uniform distribution of required temperature inside the refrigeration compartment is performed; this excludes occurrence of different temperature zones and enables to ensure the best keeping of products. Temperature drops inside the refrigeration compartment can be maximum of 1-2°С that much differs dynamic cooling system from the static one.
Moisture that is removed by fans from the compartment of the refrigerated table settles in a form of frost directly on the evaporator without condensation, and as far as fans are switched alternatively with heaters frost is defrosting and evaporated quickly draining on purpose designed channels.
This feature of dynamic cooling system enables to avoid frequent manual defrosting of the refrigerated table. Most of the manufacturers of such equipment with dynamic cooling recommend to perform its defrosting only once or twice per year in preventive purposes.
It is important to note that unlike the static cooling that is used only in refrigerating systems, the dynamic cooling is equally used in freezing equipment too; such a flexibility gives one more advantage to the dynamic cooling systems.
In summary we realize that products are cooled better and faster in refrigerated tables with dynamic cooling system, because forced air cooling is available and refrigeration reaches the most hidden places in the refrigeration compartment of the table.
Shoud be noticed that refrigerated tables with dynamic cooling system are a little more expensive than with static cooling. Orest is the only domestic trademark in Ukraine that offers refrigerated table with dynamic cooling system.