Cold storage below zero and above zero

Cold storages are part of today's industry and it is not possible to store some perishable food, medicine, fruit and meat without using a cold storage. Today, using a refrigerator for a home has become a necessity. On the other hand, the use of cold storage is also important in today's industry. Industrial cold storage is divided into two categories: cold storage below zero and above zero.

• The compressor of the refrigerators is different from each other. In this way, the compressor below zero has less capacity and power than above zero. • The power of the compressor winding is the same in the cold room below zero and above zero. But because the sub-zero compressor has a lower discharge pressure, the diameter of the compressor cylinder has been designed to accommodate more gas. • The temperature of cold storages below zero is usually between minus 18°C ​​and minus 20°C. But in cold storages above zero, the air temperature is from 1°C to 5°C and in some cases up to 10°C. there are • The distance between the fins in cold stores is different. In this way, the distance between the fins above zero is slightly more than below zero. The reason for this distance is to prevent the formation of frost on the surface of the operator and to reduce the temperature of the cold room. • Cold rooms above zero are used to store fruits, medicine, vegetables, dairy products, etc. But below zero is used to store and freeze chicken, meat, fish, etc. • The next difference between the subzero cold room and the above zero cold room is in the size of their valve expansion needle.

The cold storages are divided into two categories below zero and above zero.

Usually the temperature of this type of cold storage is between minus 18 degrees Celsius and minus 20 degrees Celsius. In some cases, with the use of two-stage compressors and special refrigerants, it is possible to reach minus 40 degrees Celsius. This type of cold storage is usually used for long-term storage and freezing of various meat and protein products, food, etc. In terms of structure, the subzero cold storage can be: ● Small cold storage ● Container cold storage ● Industrial cold storage categorized.

This type of product is usually used in places such as hypermarkets, stores, etc. Equipping this type of cold storage is done by a unit. Also, the storage time of food in this type of cold storage is short, and this type of cold storage is not used for storing food for a long time.

This type of cold storage is used to store food in oil platforms and vessels for a longer period of time. There is no limit in terms of dimensions and size in the construction of cold storage containers, but container cold storages are only produced in two sizes, 20 feet and 40 feet.

These types of cold storages are designed and built in larger dimensions and sizes for long-term storage of products and food. In this way, the construction of their refrigeration production system is done in two ways, multi-unit or rack. This type of cold storage is usually used to store protein materials (meat, fish, chicken, etc.) or some fruits and dried fruits for a longer period of time.

In this type of cold storage, a compression system is used to control and keep the ambient temperature constant (several degrees above zero). Cold storage above zero is used to store products that require temperatures above zero, such as fruits, vegetables, medicine, etc.

The temperature of the cold room above zero is between 1 and 5 degrees Celsius. Of course, there are other samples that are rarely used and have a temperature between zero and 10 degrees Celsius. These types of cold stores have a capacity of 10,000 to 20,000 tons of refrigeration. The equipment used in this type of cold storage is similar to subzero cold storage. The only difference is the amount of energy used to control the ambient temperature, this type of refrigerator uses less energy to reduce its ambient temperature. It should be noted that the use of this type of cold storage is done in a short period of the year, and for this reason, there is no need to use some fluids and to insulate the walls.

• Air flow and ventilation paths are directly related to the operation of the cold room above zero. In this way, for the optimal performance of cold storage rooms, it is better to be equipped with air circulation display equipment inside the cold storage room. • These cold storages are generally produced in multi-story form. The air temperature of the lower floors is lower than other places due to the convective air flow, and it is suitable for storing food that needs a lower temperature. • Food freezing time in freezing tunnels is different from cold storage. In the freezing tunnel at low temperature, the speed of the freezing process is very high, but in cold stores, this process is done at a relatively slower speed. • The cold storage system is equipped with a thermometer. And by means of it, the temperature of different parts of the cold store is measured and reported at any moment. • In some cold stores, carbon dioxide gas is injected into the room. This action is done to reduce the concentration of some gases such as oxygen.