Abstract: A heating device for food and other products is provided. The device includes a unit containing a rechargeable phase change material which is capable of being charged with heat energy by a heat source such as a conduction, convection, radiant heat, electrical resistance, electrical inductance, microwave, or radio frequency. The phase change material may be provided in a variety of forms and may comprise linear alkyl crystalline alkyl hydrocarbons, alkyl hydrocarbon waxes, crystalline fatty acids, linear crystalline primary alcohols, ethylene copolymers, polyethylene, polyethylene glycol, polyethylene oxide, and acetamide.

Abstract: A rechargeable phase change material unit is provided. The unit comprises a first shell portion and a second shell portion forming a hollow shell defining a cavity. At least one layer of a phase change material is disposed in the cavity of the shell. The phase change material is capable of being charged with heat energy. A heater assembly is positioned on one side of the layer of phase change material. The heater assembly is provided to charge the phase change material with heat energy and distribute heat energy throughout the layer of phase change material during the charging of the phase change material.