Building a cold room using sandwich panels is one of the most optimal and modern methods of creating food storage space. Sandwich panels, which are composed of outer layers of metal sheet and core of polyurethane insulation, are a suitable choice for building the walls and roof of cold stores due to their excellent insulation properties. By reducing the heat exchange, these panels maintain the internal temperature of the cold store in a certain range and prevent energy loss.

In addition to saving energy, using sandwich panels in cold storage has other advantages. These panels reduce construction time and costs due to their light weight and quick installation. Also, their high resistance to moisture, corrosion and decay increases the lifespan of the cold storage. Other important features of sandwich panels are washability, hygiene, and flexibility in design, which make them an ideal option for food and fruit storage cold rooms.

Polyurethane (PU) is a type of insulating foam in which most of the pores are closed and can be used as thermal insulation. It is made from a combination of polyol and isocyanate under special conditions and in the presence of a catalyst, and it has better advantages than polystyrene. . A sandwich panel made of polyurethane insulation has the ability to last in an air temperature of 100-110 degrees Celsius.

Polyurethane sandwich panel is a better insulator compared to polystyrene sandwich panel, so it is better for building cold storage with thinner walls. Also, in the construction of polyurethane sandwich panels, polyurethane insulation is directly attached to metal sheets without any type of glue and is stable over time. In the case of the polystyrene sandwich panel, glue is used to attach the insulation, which may peel off over time and under environmental conditions.

One of the most important factors for cold storage is always maintaining a low temperature in the cold storage and the ability to adjust the temperature in it to take care of the objects inside. Cold stores are often used in food, pharmaceutical, hospitals, etc. factories. Sandwich panel is good for cold storage due to its useful properties, which easily keeps the internal temperature of the cold storage at a certain value due to the low heat transfer coefficient of the sandwich panel.

Cold stores are usually used in two types, short-term and long-term. This type of naming is based on their internal temperature and the shelf life of each product. The short-term cold storage has a temperature between 1 and 4 degrees Celsius. In this type of cold storage, products are kept for a maximum of 15 days and are used for food such as fruits and vegetables and dairy products.

Food can be frozen slowly or quickly. In the slow freezing method, the desired materials are placed in a low temperature space to slowly freeze. There are also different ways for quick freezing, including direct contact of the product with the freezing agent, indirect contact of the product with the freezing agent, and the passage of strong cold air. The flow of cold and intense air usually takes place in a special tunnel called the freezing tunnel. In this method, the temperature drops to minus 40 degrees.

The above-zero cold room is used as a pre-cooler for protein products, dairy tunnel, storage of fruits and vegetables, while the freezing tunnel is used for storage of protein products, shock freezer, storage of ice cream and chocolate, storage of frozen products. The type of insulation of the body in both types of cold storage is usually done by sandwich panel.