Flowers processing vacuum cooler
Vacuum cooler & Hydro-vacuum cooler brief introduce
Vacuum cooling involves reducing the pressure inside an airtight chamber. The water inside the vegetables is transformed into steam that absorbs heat energy. Vacuum cooling is best for products that easily lose water, such as lettuce and young seedlings.
Hydro-vacuum chillers add a misting system to prevent moisture loss from the product. At the same time, hydraulic cooling can help cool more quickly and make some compact vegetables suitable for the vacuum cooling process.
Vacuum cooling is a fast and energy efficient method.
What is vacuum cooling? (In detail)
Vacuum cooling removes heat from vegetables by boiling some of the water they contain.
The product is loaded into a sealed vacuum chamber and the air is pumped. This reduces the normal air pressure to a virtual vacuum (<1KPa). Under these conditions, the water boils at less than 7 ° C.
When the water in the vegetables changes from a liquid to a gaseous state, it absorbs the heat energy of the product and cools it. This vapor is removed by passing it past the refrigeration coils, which condenses it in liquid water.
For vegetables to cool quickly under vacuum, they must be able to easily lose moisture. For this reason, vacuum cooling is very suitable for leafy products such as lettuce, Asian vegetables and fresh cut flowers. Products such as broccoli, celery and sweet corn can also be effectively cooled by this method. Vacuum cooling is not suitable for products with waxy skin, low surface area / volume, e.g. carrots, potatoes, tomatoes or zucchini.
For each temperature reduction of 5 ° C, approximately 1% of the product weight must be converted to water vapor. However, modern water-cooled chillers solve this problem by spraying water on the products during the vacuuming process. This can reduce moisture loss to negligible levels.