A cold food chain is a temperature-controlled supply chain, which helps extend and ensure the shelf life of food products. It starts from food production and ends in domestic refrigerators.
From insulating animal sheds to distribution of refrigerated containers via storage in cold stores, to local storage in supermarkets, and ending in domestic refrigerators, freezers or portable coolers, polyurethane insulating foam plays its role.
Polyurethane foam is not only a versatile material which exhibits desired processing characteristics such as toughness, it also offers a unique combination of lightweight and closed cell structure with encapsulated insulating gas. This is the primary reason for its very favorable insulation-to-thickness ratio, which saves space and material while achieving required insulation values. The mentioned advantages have resulted in polyurethanes being the predominant insulation material and construction element for many of the individual "parts" in the food chain - up to 100% so in some of them.
Polyurethanes are widely used in the insulation of buildings used for rearing chickens. In cold climates it maintains higher temperatures to help young chickens resist the elements, while in hot climates it preserves a cooler atmosphere to promote growth. As fishing vessels have to increasingly fish further from their home ports, polyurethanes insulated holds keep the catch fresh until it is landed.
Fresh vegetables, fruit, butter, milk and various types of meats can be stored before distribution to shops or restaurants in large refrigerated warehouses or cold stores. These buildings are essential to keep year-round stocks of fresh products. Cold stores are almost always built using steel-faced, polyurethane cored sandwich panels. The polyurethane cores may be 200 mm-thick so as to maintain freezing conditions while minimising energy consumption Due to their excellent thermal properties, polyurethane panels in cold stores and other chilled facilities offer temperature controlled environments. Panels are available in a wide range of thicknesses, depending on the kind of temperatures that need to be maintained.
In today’s global economy, food has to be transported over large distances by sea, rail, road and even by air. The containers (sometimes called reefers) and truck bodies used must be robust to withstand rough treatment, be energy efficient and have highly effective insulation because space is almost invariably limited. Dimensions are standardised and palettes just fit within them. Polyurethane is the standard material used, not only to ensure insulation but also to contribute to the strength of the container and prolong its service life. Polyurethane containers provide superior maintenance of internal payload temperatures for long time periods, even under extreme weather conditions. They are an ideal choice to maintain payloads between 2°C to 8°C during demanding shipping conditions. Polyurethane’s high thermal resistance value is unmatched by other foams.
Cold rooms are used in large stores and supermarkets to store fresh and frozen produce for a few days before sale. These rooms are almost always constructed from polyurethane-cored sandwich panels and are designed for maximum internal space and minimised energy consumption. Supermarkets will also have refrigerated cabinets for the display of food. These can be cooled to either refrigerator (+4°C) or freezer (-18°C) temperatures. The refrigerated cabinets are insulated with a high-density, closed cell, expanded polyurethane foam, which offers a high insulation factor. Even the doors have a special film between the layers of glass to keep the cold in and the heat out. As the energy consumption of the refrigeration equipment represents an average of 35-50% of the total energy consumption of an average supermarket, polyurethane insulation can substantially minimise energy consumption and cut energy costs.
Domestic refrigerators and freezers are a familiar and invaluable part of the cold food chain. Polyurethane foam is widely used in domestic refrigerators and freezers, providing essential insulation for the low temperature preservation of food. The high insulation value of polyurethanes maximises the internal volume while minimising energy consumption.