CONSTANT TEMPERATURE HEAT STORAGE IN METAL HYDRIDES

ADVANCED THERMAL STORAGE IS A CRUCIAL ELEMENT OF FUTURE SPACE POWER SYSTEMS. SOLID-LIQUID PHASE CHANGES IN HIGHLY CORROSIVE SALTS, SUCH AS LIF, ARE FAR FROM IDEAL FOR SUPPLYING THE THERMAL DEMANDS OF DYNAMIC POWER CONVERTERS. IN THEORY, PHASE CHANGE MATERIALS STORE HEAT ISOTHERMALLY BUT UNDERCOOLING AND HEAT TRANSFER TS CAUSE SIGNIFICANT TEMPERATURE DEVIATIONS. METAL HYDRIDES ARE COMPETITIVE WITH MOLTEN SALTS IN TERMS OF WEIGHT AND SUPERIOR IN TERMS OF HEAT STORED PER UNIT OF VOLUME. THE MOST IMPORTANT ADVANTAGE OF HYDRIDES IS THEIR ABILITY TO RETURN HEAT TO THE RECEIVER OF A DYNAMIC CONVERTER WITHOUT A REDUCTION IN TEMPERATURE. THIS EFFECT MAY BE ACHIEVED BY DEVELOPING PAIRS OF METAL HYDRIDES, OPERATING INTANDEM TO PUMP WASTE HEAT FROM THE RADIATOR LOOP TO THE RECEIVER. A TEMPERATURE SWING IN ONE OF THE TWO HYDRIDES OVERCOMES THE IRREVERSIBLE ENERGY LOSSES OF STORING AND RECOVERING HEAT FROM THE OTHER. IN EFFECT, THIS PROVIDES ISOTHERMAL HEAT STORAGE, MAINTAINING FULL RATED OUTPUT FROM THE POWER SYSTEM WHILE THE STORED HEAT IS RECOVERED. THE PHASE I R&D WORK WOULD PROVIDE A BASIS FOR COMPARISON TO ALTERNATE CONCEPTS, AND FOR THE FABRICATION OF A GROUND TEST ARTICLE IN PHASE II.