The drying system developed in Norway is filled with frozen raw materials. The process of dehydration starts in a chamber kept at sub-zero temperatures, which makes the food highly porous and gives it good capacity to absorb water again in the cooking pot. The process is completed in a chamber at a temperature kept above freezing point, in order to reduce the drying time.
The combination of high quality and low price sounds like an impossibility. Nevertheless, the Norwegian scientists managed it, by combining two technologies.
Fluidized bed: The particles to be dried are suspended in a vertical current of gas. This dehydrates them on all sides at once, shortening the drying time and increasing the capacity of the system.
Air treatment in heat pump: The drying air circulates in a closed loop connected to a heat pump. The air acquires the correct properties for drying when it meets the hot side of the heat pump. It is then dehydrated again as it passes through the heat pump’s cold side, reducing energy consumption.