abstract |
The invention provides compositions for use in thermal energy storage systems, including thermal energy storage mediums, fluid channeling devices and thermally conductive heat transfer elements, and methods for storing thermal energy. A thermal energy storage system is provided, comprising: (a) a granular thermal energy storage medium comprising at least a first size class and a second size class; wherein the individual granules of each size class deviate from the average granular size for that size class by no more than about ±50%; wherein first size class is the largest size class; wherein the ratio of the average size of the first size class to the average size of the second size class is at least about 2:1; and (b) one or more conduits disposed within the medium, and arranged to receive a source of thermal energy. |