Thermal energy storage technology developments

This paper describes recent technology developments in thermal energy storage devices for use on spacecraft for thermal control of electronic components requiring thermal stability. A thermal energy storage module has been designed, built and tested using lithium nitrate as the melt material and carbon foam as the conductive filler. For this unit the observed melt temperature was around 30 degrees C. The supercooling property of lithium nitrate was reduced by adding zinc nitrate as a catalyst. The hydrophobic nature of the carbon foam was overcome by adding a surfactant to the lithium nitrate. The resulting energy storage capacity of the prototype module during the melt was 40 W-hr/kg. There was very good thermal conductivity through the module resulting in very low temperature gradients even at high power levels.