Vacuum cooling

Application

Vacuum cooling of mushrooms, vegetable, fruit, tobacco and flowers;

The question

Vacuum coolingMany organic products are freshly grown and harvested. The product begins to decompose directly after harvesting because it wants to continue growing but receives no further nourishment. The growth process which is stimulated by temperature is slowed down greatly by 2- 4 degrees. The product is therefore wheeled into the cold store on pallets directly after harvesting where it reaches the required temperature in 8 – 10 hours. It is important that the cooling occurs as uniformly as possible so that the core of the product is reached.

The faster the cooling process occurs, the lower the reject percentage and the higher the quality; but it is not possible to cool any quicker using the standard cooling technology. After all the process comes about by means of heat emission from the outside to the inside and there are large barriers due to the products being put into crates on pallets.

Indigo Engineering vacuum cooling

With vacuum cooling, Indigo Engineering offers the perfect solution for organic products with an open structure and consisting for the most part from water. The cooling principle is based on the evaporation of a very small part of this moisture. The evaporation energy generated by evaporation has to be supplied but there is no heat exchange because the product is isolated in the vacuum chamber. That is why the evaporation energy is extracted from the residual product.Vacuum cooling

Products such as mushrooms, vegetables, fruit, tobacco and flowers are products with relatively low specific heat in respect to water. This means that little water evaporation is required for a relatively high temperature drop. Most of these products have a very high moisture content and an open structure which advances the evaporation speed and uniformity after cooling. Vacuum cooling is an ideal method for this type of product. It is uniform, quick, easy to regulate, reproducible and requires little energy per kilogram of product to be cooled.

Characteristics – advantages

  1. Very stable and accurate final temperature for different loads and conditions.
  2. Short cycle time.
  3. Low maintenance costs.
  4. Low energy costs.
  5. Own concept vacuum chamber made from stainless steel, built to fit the application.
  6. Robust design.
  7. Modern software based on the final temperature of the product.
  8. Experience in cooling mushrooms, vegetables, fruit and tobacco.

High quality technology

Indigo Engineering has developed a turnkey solution for this process after long-term testing on a practical scale with various mushroom growers and organic companies. A vacuum cooling installation consists in the main of:

  • A vacuum chamber or vacuum tunnel.
  • Condensation installation unit with larger vacuum chambers.
  • Vacuum pump installation.
  • Control.
  • Logistic part, feed and discharge.

The vacuum chamber is made entirely from stainless steel and therefore easy to clean. In addition rust will not form on the inside if damaged.

The vacuum pump system is explained per situation for the required capacity, temperature and load. In addition Indigo takes optimal account of the local conditions in the customer’s environment.

Indigo has specifically developed the software for the full automatic control of this application. The software takes into account product variables which differ per load: more or less moisture, more or less load, difference in starting temperature. The suction power of the installation is regulated for the abovementioned variables in such a way that the product’s final temperature after this process is always the same and is reproducible. We can supply various systems for feeding the product into the vacuum chamber, depending on the local situation. In normal practice, cooling cycles of 15 – 60 minutes are achievable.

References

Several manufacturers in the agriculture industry apply this system now. Ask our customers about their experiences.