High-capacity high-power thermal energy storage using solid-solid martensitic transformations

A new concept of fabricating thermal energy storage modules using high-conductivity, solid-solid, shape memory alloys is demonstrated here to eliminate the capacity-power tradeoff common in solid-liquid designs. First, three compositions Nickel titanium were solution heat treated and characterized differential scanning calorimetry Xenon Flash down-select a promising material (Ni50.28Ti49.36) with transformation temperature 78 ˚C, volumetric latent 183 MJm−3, conductivity Austenite Martensite phases 12.92 12.64 Wm−1K−1, respectively. Next, four parallel-plate demonstrators designed, fabricated, tested thermofluidic test setup. These include baseline sensible heating module (aluminum), conventional PCM (aluminum/1-octadecanol), an all-solid-solid (Ni50.28Ti49.36), composite solid-solid/solid-liquid (Ni50.28Ti49.36/1-octadecanol). We are able demonstrate 1.73–3.38 times improvement capacity 2.03–3.21 power density by NiTi. experimental results bolstered analytical models explain observed transfer physics, extrapolate additional use cases, reveal 5.86 time constant. This work demonstrates ability build high-capacity high-power multifunctional opens door for leap ahead transient management.