Heat capacity per unit volume has been increased.

A heat-storage module based on a commercial open-cell graphite foam (PocoFoam or equivalent) imbued with lithium nitrate trihydrate (LiNO₃•3H₂O) has been developed as a prototype of other such modules for use as short-term heat sources or heat sinks in the temperature range of approximately 28 to 30 °C. In this module, the LiNO₃•3H₂O serves as a phase-change heat-storage material and the graphite foam as thermally conductive filler for transferring heat to or from the phase-change material. In comparison with typical prior heat-storage modules in which paraffins are the phase-change materials and aluminum fins are the thermally conductive fillers, this module has more than twice the heat-storage capacity per unit volume.