US Patent 7491912 Portable container with temperature control chamber

A portable food delivery container includes a food storage compartment, a control compartment, and a temperature control source. A control compartment lies adjacent to and in thermal conductivity with the food storage compartment. A modular removable temperature control source is disposed within the control compartment, where the temperature control source effects transfer of thermal energy between the food storage compartment and the control compartment to maintain the food storage compartment at a temperature other than the ambient temperature.