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.

Abstract: A method of pumping a heat transfer fluid in a thermal energy storage system comprising a first thermal energy storage tank connected to a second thermal energy storage tank via a bi-directional flow member. The first and second thermal energy storage tanks are associated with a pressure vessel system comprising a first and second pressure vessel each pressure vessel being partially fillable with an actuating liquid, wherein, the method for pumping comprises: displacing the actuating liquid from the first pressure vessel to the second pressure vessel, thereby creating a pressure difference in the first thermal energy storage tank with respect to the second thermal energy storage tank, and therein displacing the heat transfer fluid via the bi-directional flow member.

Abstract: A method of pumping a heat transfer fluid in a thermal energy storage system comprising a first thermal energy storage tank connected to a second thermal energy storage tank via a bi-directional flow member. The first and second thermal energy storage tanks are associated with a pressure vessel system comprising a first and second pressure vessel each pressure vessel being partially fillable with an actuating liquid, wherein, the method for pumping comprises: displacing the actuating liquid from the first pressure vessel to the second pressure vessel, thereby creating a pressure difference in the first thermal energy storage tank with respect to the second thermal energy storage tank, and therein displacing the heat transfer fluid via the bi-directional flow member.