In some embodiments, a refrigeration device includes: walls substantially forming a liquid-impermeable container configured to hold phase change material internal to the refrigeration device; at least one active refrigeration unit including a set of evaporator coils positioned at least partially within the liquid-impermeable container; a unidirectional thermal conductor with a condensing end and an evaporative end, the condensing end positioned within the liquid-impermeable container; a first aperture in the liquid-impermeable container, the first aperture of a size, shape and position to permit the set of evaporator coils to traverse the aperture; a second aperture in the liquid-impermeable container, the second aperture including an internal surface of a size, shape and position to mate with an external surface of the unidirectional thermal conductor; and one or more walls substantially forming a storage region in thermal contact with the evaporative end of the unidirectional thermal conductor.