US Patent 10549900 Insulated storage and transport system

A thermal storage system includes a thermally insulated storage container and a payload container adapted to retrievably house a temperature sensitive payload. The system includes layers of first and second phase change materials arranged in a stack with the payload container. The first phase change material has a phase change temperature within a target temperature range of the payload, and the second phase change material has a phase change temperature outside the target temperature range. The layers are arranged to isolate the payload from the second phase change material. In the case of biological materials that must not freeze while stored in the container, this arrangement enables a cold pack containing the layers of phase change materials to be placed in direct contact with the contents container even with a cold pack starting temperature well below the freezing point of the contents.