Vacuum Cooling System

The application of vacuum cooling technology has caused a revolution in the green vegetables cold chain distribution system. In summer time, vegetables tend to deteriorate very fast after harvest from the field under high temperature.

Principle of vacuum cooling

It is therefore, necessary to cool the vegetables down  to about 0°C within a short time to preserve its freshness.The most effective method to cool down vegetables is under  vacuum through self-evaporation of water.The “main principle is when a vacuum chamber  is filled with green vegetables and evacuated, the free water in the cell tissues of the vegetables   begins to evaporate at a pressure  and the vegetables cool themselves due to the latent heat of the  evaporating water.Since  597 Cal  is required  to vaporize 1 gram  of water at 0°C, the vegetables are  cooled to  0°C in about  20-30  minutes when the chamber is maintained ~t a pressure of about  4.6 Torr. The large  amount of water  vapor  generated inside  the chamber is condensed  on the surface  of the cold  trap  and removed  from the chamber. The system uses a refrigerator  to keep the cold trap at a low temperature.

Advantage of Vacuum Cooling