Abstract: An assembly for storing thermal energy comprising a phase change material, PCM, storage vessel and at least one heat transfer fluid, HTF, receptacle, the PCM storage vessel being defined by a thermally conductive wall 108, the PCM storage vessel 100 comprising an inverted tapered portion, the inverted tapered portion having a tip portion and a base portion, the tip portion having a diameter less than the diameter of the base portion, the tip portion being arranged relatively beneath the base portion, the at least one HTF receptacle being provided adjacent to and in thermal communication with at least a portion of the PCM storage vessel, thermal communication between the PCM storage vessel and the at least one HTF receptacle occurring via the thermally conductive wall, and wherein the HTF receptacle comprises a portion for receiving thermal energy from an external thermal energy source, the said the portion being adjacent the tip portion of the inverted tapered portion.

Abstract: An assembly for storing thermal energy comprising a phase change material, PCM, storage vessel and at least one heat transfer fluid, HTF, receptacle, the PCM storage vessel being defined by a thermally conductive wall 108, the PCM storage vessel 100 comprising an inverted tapered portion, the inverted tapered portion having a tip portion and a base portion, the tip portion having a diameter less than the diameter of the base portion, the tip portion being arranged relatively beneath the base portion, the at least one HTF receptacle being provided adjacent to and in thermal communication with at least a portion of the PCM storage vessel, thermal communication between the PCM storage vessel and the at least one HTF receptacle occurring via the thermally conductive wall, and wherein the HTF receptacle comprises a portion for receiving thermal energy from an external thermal energy source, the said the portion being adjacent the tip portion of the inverted tapered portion.