Abstract: A method comprising feeding a liquefied refrigerant gas into direct contact with aqueous liquid in an enclosed vessel to chill or cool the liquid and/or produce ice crystals and vaporize the refrigerant by heat exchange with the aqueous liquid; feeding a mixture of cold aqueous liquid and/or ice and refrigerant from the vessel to an enclosed storage tank to provide cold aqueous liquid and/or ice therein; removing refrigerant vapor from the storage tank; converting the refrigerant vapor to liquid refrigerant in a refrigeration cycle and feeding the liquid refrigerant back to the enclosed vessel; and withdrawing aqueous liquid from the storage tank and feeding it to the enclosed vessel; with all said refrigerant and aqueous liquid streams and volumes being in a single closed system such that refrigerant and aqueous liquid are not lost except by inadvertent leaks and consumption of such materials is avoided because they are not withdrawn from the system.

Abstract: Apparatus comprising a freeze exchanger having an aqueous liquid feed stream inlet and an aqueous liquid stream outlet; a closed loop refrigeration system for supplying a refrigerant to the freeze exchanger for indirectly cooling aqueous liquid fed thereto; an ice storage tank; a conduit for withdrawing aqueous liquid, or a mixture of ice and aqueous liquid, from the freeze exchanger outlet and delivering it to the ice storage tank; a conduit for removing cold aqueous liquid from the ice storage tank and feeding it to a heat exchanger to cool fluid used for cooling purposes; and a conduit for removing warm aqueous liquid from the heat exchanger and feeding it to the ice storage tank, or to the freeze exchanger, or partially to both.A method of cooling making use of the apparatus is also disclosed.