High performance metal hydride based thermal energy storage systems for concentrating solar power
AssigneeSavannah River Nuclear Solutions, LLC
InventorRagaiy Zidan
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Abstract
Thermal energy storage (TES) systems based on metal hydride pairs using new class of high efficiency materials are evaluated. The use of low temperature metal cost effective material such hydrides NaAlH4 and Na3AlH6 became possible. In order to obtain high efficiency at reasonable cost high temperature materials were altered by the addition of materials to form reversible alloys and hydrides. The compounds were cycled to determine stability of hydrogen capacity over extended number of cycling. A thermal energy storage system based on two metal hydride pairs such as CaAl/CaH2/Al:NaAlH4, Ca2Si/CaH2/Si:Na3AlH6 and NaMgH2F—Si/Mg2Si—NaF:Na3AlH6 allows low cost and high efficiency performance.
Claims8
A process of using metal hydride mixed with different elements to form a mixture to be used in thermal energy storage systems comprising:
- providing a dual bed hydride reactor having a HEH reaction bed and a LEH reaction bed, the HEH reaction bed containing a mixture/composite of at least one hydride selected from the group consisting of NaMgH3, MgNaFH2, TiH2, LiH, MgH2, CaH2, and combinations thereof and an element selected from the group consisting of Al and Si and the LEH reaction bed containing at least one of a metal hydride selected from the group consisting of NaAlH4, Na3AlHe4, FeTiHx, MmNi6H5 and combinations thereof;
- adding heat to the HEH reaction bed containing the mixture/composite to release hydrogen gas from the hydride in the mixture/composite and to form a reversible alloy comprising the element in the mixture/composite and elements from the hydride after dehydrogenation in the mixture/composite;
- transferring the released hydrogen gas from the HEH reaction bed to the LEH reaction bed;
- and
- dehydriding the LEH reaction bed and absorbing hydrogen released from the LEH reaction bed with the HEH reaction bed causing an exothermic process of the reversible alloy reversing to the element and the hydride of the mixture/composite such that heat yielded back from the exothermic process reaches temperatures between 650° C. to 800° C.
Dependencies are inferred from the claim text.