Abstract: A passive refrigeration apparatus comprising: (i) a container defining a cargo space; (ii) a liquid carbon dioxide cylinder; (iii) a control valve, in fluid communication with the cylinder; (iv) a controller for activating the control valve to control the flow of liquid CO2; and (v) a heat transfer assembly within the container, in fluid communication with the control valve; wherein the heat transfer assembly has (a) an expansion section for receiving the flow of liquid CO2; and (b) an expansion chamber bounded by a heat transfer surface in thermal contact with the cargo space; wherein the expansion section allows the vaporization of the liquid CO2 into the expansion chamber to create a mixture of carbon dioxide snow and CO2, thereby cooling the cargo space via the heat transfer surface.

Abstract: A passive refrigeration box for controlled refrigeration of a product comprising: an outer box including an outer insulation layer; an inner box including an inner insulation layer, and a thermal shield on an outside of the inner insulation layer, the inner box and the outer box defining a vapour channel therebetween; and a thermal link including a thermal layer and a plurality of heat pipes or thermosyphons, the thermal layer and a top section of the inner box defining a coolant chamber, the coolant chamber including a coolant chamber access, and in communication with the vapour channel, and the thermal layer and a bottom section of the inner box defining a load chamber, the load chamber including a load chamber access, each heat pipe or thermosyphon having a condenser section disposed in the coolant chamber and an evaporator section disposed in the load chamber and extending through the thermal layer.