Vacuum cooling works by lowering the boiling point of water from 212 degrees F to as low as 32 degrees. As the vacuum level reaches the flashpoint of vapor at say 85 degrees, water in the produce boils giving off steam. The steam travels toward the vacuum pumps. Prior to getting to the vacuum pump suction, the steam is condensed on a refrigeration coil which runs ideally at 10 degrees below the product temperature.
As the steam is drawn from the produce, heat is removed. The vacuum level continues to fall as does the product temperature until the predetermined setpoint is reached and the cycle ends. Our systems are automated. A temperature is set, a probe inserted into the product and a start button is pressed.
Our chambers are designed to run dry cycles, dry cycle with a small amount of water sprayed over the pallets, a wet cycle where high volumes of water are distributed over the pallets, and then finished off with vacuum, or used as a hydro-cooler. As a hydro-cooler the vacuum pressure is lowered to seal the chamber door, and onboard pumps recirculate water over the pallets to cool the produce inside.