Evaporator in IQF Tunnel Freezer

Evaporator in IQF Tunnel Freezer

In an IQF (Individual Quick Freezing) tunnel freezer, the evaporator is a key component responsible for the heat exchange process that enables rapid freezing of the products.

The evaporator in an IQF tunnel freezer typically consists of a series of fin - and - tube coils. The tubes are usually made of copper or aluminum for good thermal conductivity. They are arranged in a U - shape or other configurations to maximize the heat transfer area within the available space. The fins, which are often made of aluminum, are attached to the tubes to increase the surface area in contact with the air or the product being frozen, enhancing the heat transfer efficiency.

The evaporator works based on the principle of refrigerant evaporation. The refrigerant, such as ammonia or a fluorocarbon, enters the evaporator in a liquid state at a low pressure. As it flows through the tubes of the evaporator, it absorbs heat from the surrounding air or the products passing through the tunnel. This heat absorption causes the refrigerant to evaporate, changing from a liquid to a vapor state. The heat is transferred from the products or the air to the refrigerant due to the temperature difference between them.

In an IQF tunnel freezer, the products to be frozen are conveyed through the tunnel on a conveyor belt. As the products pass over the evaporator coils, the cold surface of the coils extracts heat from the products, causing the water within the products to freeze rapidly. The low temperature of the evaporator, maintained by the evaporating refrigerant, ensures that the products are frozen quickly enough to form small ice crystals, which helps to preserve the quality and texture of the products.

The refrigerant vapor, after absorbing heat and evaporating, exits the evaporator and is then drawn back to the compressor in the refrigeration system. The compressor raises the pressure and temperature of the refrigerant vapor, preparing it for the next stage of the refrigeration cycle, which is usually condensation in the condenser.