Music fills the back­ground, the appro­pri­ately colored lighting softly illu­mi­nates the flashy product pack­aging. The super­market freezer cabinet hums reli­ably — after all, the temper­a­ture must not exceed minus 18 degrees Celsius. This is how a refrig­er­a­tion chain must func­tion to deliver on its promise to main­tain the food’s quality.

Fresh food is used to produce frozen food. Meat, fish, vegeta­bles and fruit. In order to main­tain their quality over a longer period of time, the blast freeze process is used. The food is chilled to below – 18 degrees Celsius in a very short time. In the case of flow freezing, icy air currents with temper­a­tures as low as – 40 degrees Celsius are used.

For refrig­er­a­tion circuits

Bohn manu­fac­tures the compo­nents for refrig­er­a­tion circuits like these for its customers. In Mexico, Bohn is a specialist in the refrig­er­a­tion tech­nology sector and sells various systems for ware­houses and cold-storage rooms, containers and vehi­cles to food logis­tics compa­nies. In the process, Bohn is faced with the tech­nical chal­lenge of bringing large rooms down to frost temper­a­ture to produce frozen foods. Lots of air has to be chilled quickly.

320,000 cubic meters in less than five hours until minus 35 degrees Celsius.

For example, the temper­a­ture in a hall measuring 320,000 cubic meters — 200 meters long, 80 meters wide and 20 meters high — must be chilled from + 20 degrees Celsius to – 20 degrees Celsius in less than two hours. The room must be chilled for three more hours until the temper­a­ture is – 35 degrees Celsius. Then the room temper­a­ture must be main­tained. Since 2016, Bohn has equipped its blast freezer evap­o­ra­tors with EC fans from ebm-papst.

Large, effi­cient and adjustable

The medium pres­sure axial fan has proven to be the most suit­able variant because it is large, effi­cient, has an extremely high throw and can be controlled. With a diam­eter of 1,120 mm, it can trans­port an air volume of up to 50,000 cubic meters per hour at a back pres­sure of between 200 and 550 Pa.

To move the air in the gigantic ware­house, three evap­o­ra­tors are installed directly under the ceiling on each side of the building. Three fans turn in each evap­o­rator, yielding a total of 18 fans. They are oppo­site each other in order to reach every corner of the hall and each one has a throw of 40 meters. Temper­a­ture sensors control the fan speed in order to keep the temper­a­ture stable.

Fresh food packed with vita­mins

The food in the super­market freezer cabinet reveals nothing about this tech­ni­cally sophis­ti­cated task and consumers learn about it only indi­rectly. They can enjoy prod­ucts full of vita­mins, nutri­ents and aroma.