I am student studying at a University in Singapore. Right now I am planning to build small capacity (100 to 200 Kg) mobile vacuum precoolers for farmers in my home town back in India, they are facing wastage of vegetables (spinach, coriander and herb leaves) due to poor postharvest management of products. By using precoolers and cold chain they will be able to export products. Can you please provide us guidance, design or other information in designing single pallet size vacuum coolers. Thank you. (P.R.)
Unfortunately there are no publicly available references for vacuum cooler design. The technology has been developed by the companies that sell the units and they do not share their designs.
Vacuum coolers are quite expensive and I would recommend building a forced air cooler for the products you mention. It is much less expensive and would cause less moisture loss from the products. You may want to package them in perforated bags to reduce wilting in subsequent handling.
A good reference for your design work is "Commercial Cooling of Fruits, Vegetables and Flowers". You can obtain a copy of it through our Postharvest Technology Center website. Click on the "Bookstore" tab to find a link to a complete description of this publication.