Fruit and vegetables are products that are in demand for a much longer period than the supply due to their ripening period. It is therefore necessary to keep them fresh for as long as possible after harvesting.

The permissible storage time depends primarily on the species, variety, harvest date and storage conditions. For most fruit varieties in our climatic zone, the optimum storage temperature is close to 0°C. Lowering the temperature reduces the rate of respiration of the fruit, which slows down ripening. The main factors influencing vegetable storage are temperature, humidity, gas composition of the atmosphere as well as storage hygiene. Reduced storage temperature reduces the respiration rate of fruit and vegetables. For most fruit and vegetables, the optimum temperature is 0°C. Temperatures below 0°C can lead to freezing and thus a reduction in quality and shelf life. The exceptions are bulb vegetables, which can be stored at temperatures below zero, e.g. onions and garlic from -2°C to -3°C, leek to -1.5°C.

A constant temperature should be maintained throughout the storage period, as freezing and thawing several times leads to tissue damage. The material commonly used for cold rooms is refrigerated sandwich panels, which are used for both walls and ceilings. This is because the cold plate has characteristics that make it ideal for such an application.

Thermal insulation

The refrigerated sandwich panel, thanks to the use of polyisocyanurate foam for its production, has a thermal conductivity coefficient of λ=0.022 [W/mK], which is unrivalled compared to other commonly available thermal insulation materials.

Izopanel Sp. z o.o. manufactures cooling panels in thicknesses from 120mm to 220mm, which makes it possible to achieve a heat transfer coefficient as low as U=0.10[W/m²K].

The very good thermal insulation characteristics have a direct impact on maintaining the desired temperature conditions inside the chambers throughout their service life and, very importantly, a cold store made from sandwich panels has a lower energy requirement to maintain the reduced temperatures.

Wide range of paint finishes

Sandwich panels for cold stores can be manufactured using steel facings that vary in thickness as well as the type of paint coating. This makes it possible to optimally configure the final product to the conditions in which it will operate.

The choice of paint coating is based primarily on the corrosivity category of the environment in which the sandwich panels will be used.

In the food industry, sandwich panels and their facings are furthermore required not to affect food in direct contact. Such features should be confirmed by appropriate certificates inserted by the PZH. For such applications, we can recommend Foodsafe coating or stainless steel cladding.

Fire resistance and reaction to fire

The refrigerated sandwich panel has a core made of polyisocyanurate (PIR). PIR is a modern material which has significantly better properties than traditional polyurethane foam in the event of a fire. This is primarily due to the minimal amount of smoke produced during a fire and the extended time it takes for the heat and flame to pass through to the other side of a composite panel with a PIR core. These properties easily translate into user safety by enabling safe evacuation.

Robustness

By combining the advantages of steel and polyisocyanurate - the components of the cold plate - we obtain a product with high strength parameters. The high load-bearing capacity allows the panels to withstand external loads such as wind or temperature differences at very large distances between the supports to which they are mounted.

Given all the properties that refrigeration panels have and the ease of installation, which contributes to a reduced investment time, it seems almost intuitive to choose this product as the primary material for the construction of cold storage facilities such as ripening rooms, sorting and storage facilities.