METHOD AND APPARATUS FOR COOLING MATERIAL USING LIQUID CO2

Apparatus for supplying a refrigeration system with a low-temperature liquid CO2. High pressure liquid CO2 is supplied from a storage vessel system to a holding chamber where the pressure is reduced to create vapor and CO2 snow, forming a low-temperature coolant reservoir. Vapor is removed from the chamber to maintain the pressure therein at about 75 p.s.i.a. or below by a compressor and returned to the storage vessel. The stored cooling power of the reservoir is then employed to meet refrigeration demand and is thereafter replenished over a period of hours. The storage principle can be incorporated into a variety of different systems. For example, additional liquid CO2 may be supplied from the storage vessel to a refrigeration system wherein vapor is created that is transferred to the holding chamber for condensation by melting the snow.