A cold room is an insulated box, the smallest a few cubic metres (restaurant, butcher) and the largest thousands of cubic metres (logistics warehouse). The four walls and ceiling are built from polyurethane-filled sandwich panels; the floor may be insulated or not depending on the room temperature; the door is chosen hinged or sliding, chilled or frozen type; for cooling a monoblock unit or an evaporator + condensing unit (split) is used.
Names by temperature: chilled storage room (0 to +4 °C: meat, dairy, fruit and vegetables), positive room (+4 to +15 °C: bananas, potatoes, chocolate), frozen storage room (−18 to −25 °C), blast freezer (−30 to −40 °C, for freezing product quickly), pre-cooling room (for removing field heat after harvest). Each temperature calls for a different panel thickness, evaporator fin spacing and defrost type.
The size of the room is set by the quantity of product: a Euro pallet takes up about 1 m², and gaps are left for air circulation at the aisles, walls and in front of the evaporator; the general rule is to fill 60–70% of the volume with product. The cooling load calculator finds the capacity needed from the room’s dimensions, product and temperature; the food storage conditions guide shows which product wants which temperature and humidity.