Abstract: A thermal energy storage facility is provided that consists of a packed bed with an essentially unconstrained outer region and a duct having a heat exchange end region located within a central lower region of the packed bed and a fluid supply end opposite the heat exchange end region. The heat exchange end region of the duct permits heat transfer fluid at an elevated temperature to pass from the duct to the packed bed during a charge cycle to heat the packed bed from an inner region outwards. The heat transfer fluid is drawn from the packed bed into the duct during a discharge cycle.