Abstract: The invention relates to a heat accumulator for storing thermal energy in at least one heat accumulator block, which heat accumulator has a removal device for removing stored thermal energy. For the uniform removal of energy from the accumulator, the heat accumulator block and the removal device according to the invention are separate from each other and can be moved in relation to each other. At least one heat-exchanger surface for transferring heat from a fluid or an electrical heating element into the heat accumulator block can be provided in the heat accumulator block. For the removal of thermal energy from the heat accumulator block, the removal device can have at least one evaporator surface for producing a phase change in a heat-transfer fluid.