Energy Storage Systems

A thermal energy store capable of accepting, storing and releasing thermal energy at a range of more than one temperature to/from at least one thermal energy source and/or sink, said thermal energy store comprising:

• A configuration of three or more thermal energy storage banks, each of said thermal energy storage banks having an operating temperature range;
• At least one or more of the thermal energy storage banks contains thermal energy storage material comprising a single material or a mixture of materials;
• wherein said thermal energy storage material in at least one bank contains at least some of one or more types of thermal energy storage material that undergoes at least one energy absorbing and/or releasing phase transition at one or more temperatures or one or more subranges of temperatures within the operating temperature ranges of each bank;
• wherein each phase transition is associated with a change in physical and/or chemical properties of said thermal energy storage material;
• and
• two or more independently controlled thermal energy transfer connections, wherein each connection comprises one or more devices for transferring heat from a lower temperature body to a higher temperature body, each connection linking two or more banks,
• wherein three or more banks are wholly and/or mainly and/or partially enclosed within a given outer bank;
• wherein each bank contains material with different phase transition temperatures;
• wherein the thermal energy store contains two nested configurations of banks;
• wherein the first configuration comprises a number of banks nested within each other with progressively cooler phase transition temperatures having the coolest bank in the center of the nesting configuration, and the second configuration comprises a number of banks nested within each other with progressively warmer phase transition temperatures having the warmest bank in the centre of the nesting configuration;
• wherein the two nested configurations are enclosed by the given outer bank having a phase transition temperature closest to one or more local environments enclosing the thermal energy store.