A refrigerant bunker comprises a refrigerant covering comprising a first thermally insulating material configured to enclose a solid refrigerant and an outer container comprising a container body and a container cover. The container body comprising an outer surface, an inner surface defining a partially enclosed space configured to accept the solid refrigerant and an opening for accessing the partially enclosed space. The container cover is configured for covering the container opening. The container body comprises a second thermally insulating material. A plurality of spacers protrude from the inner surface of the outer container in the partially enclosed space. The plurality of spacers are positioned to have gas fillable gaps between the spacers. Coolers employing the refrigerant bunker are also disclosed.