Reasons for Installing Thermal Insulation Layers in Cold Storages

Why should cold storage be insulated? It turns out that it is to reduce the influence of the outdoor temperature on the indoor environment and create a stable low-temperature environment inside the cold storage warehouse. The roof of the cold storage must be insulated.

There are two methods for setting up the insulation layer in the cold storage: one-side vapor barrier and double-side vapor barrier. The one-side vapor barrier is to set up the vapor barrier on the high-pressure side of the insulation layer, which is a common practice currently used in the external enclosure structure of the cold storage warehouse. The double-side vapor barrier is to set up vapor barriers on both sides of the insulation layer. This method is mostly used in high-temperature warehouses in cold northern areas, and can also be used in the internal partition walls between adjacent warehouses with large fluctuations in multi-purpose variable warehouse temperatures. Using this method requires that the insulation materials used should be as dry as possible. Otherwise, the water vapor in the insulation materials will condense in the insulation layer and is not easy to get out, causing the insulation materials to get damp.

This is especially important for controlled atmosphere storage, because in addition to the fact that water vapor entering the enclosure structure is not conducive to heat preservation, it will also cause changes in the gas inside the warehouse, which is not conducive to the storage of fruits and vegetables. Driven by the vapor pressure difference, the water vapor outside the warehouse will penetrate into the warehouse.

When the water vapor penetrates into the vapor barrier inside the enclosure structure and meets the cold air to reach the dew point or freezing point temperature (especially likely to occur in low-temperature cold storage), the water vapor will condense into water droplets or ice crystals in the voids and cracks of the insulation material, making the insulation material get damp and reducing the insulation performance, because the thermal conductivity of ice is about 100 times greater than that of polyurethane.

In severe cases, it will even damage the insulation layer. Therefore, in order to ensure that the insulation materials maintain good insulation performance, extend the service life, and maintain the normal use of the cold storage, it is very important to set up a moisture-proof and vapor-proof layer on the surface of the insulation layer.