Portable hand-held device for accommodating and transporting food or a beverage and method for controlling temperature

A portable hand-held device for accommodating and transporting food or a beverage, comprising

• a thermally insulated container which is configured to accommodate the food or beverage having
• a base;
• an accommodating space;
• an inner and an outer wall as well as an insulating space arranged therebetween enclosing the accommodating space, wherein the insulating space is of closed and sealed design and evacuated;
• the outer wall having a lower wall section adjacent to the base and an upper wall section distal from the base, where the lower wall section is comprised entirely of a first wall material and the upper wall section is comprised entirely of a second wall material, such that the second wall material is different from the first wall material, and
• the first wall material is provided with a heat transfer coefficient higher than the heat transfer coefficient of the second wall material;
• and
• a container closure, which is set up to close a container opening of the thermally insulated container;
• wherein a working medium is arranged in the insulating space, which, by means of an external thermal energy being supplied to a side of the outer wall facing away from the insulating space, can be transferred in a reversible manner between,
• a thermally insulating initial state, in which the working medium is in a solid state and is in physical contact with the outer wall and is not in physical contact with the inner wall, and
• a thermally conductive state, in which at least a part of the working medium is in a fluid state and has expanded and is in thermally conductive contact with both the outer wall as well as the inner wall;
• and wherein the working medium is one of paraffin or a paraffin derivative.