Selection of compatible metallic phase change materials and containers for thermal storage applications

Suitability of aluminium copper silicon eutectic as a phase change material for thermal storage applications: Thermophysical properties and compatibility

“…The volumetric energy density measured is within experimental uncertainty of that predicted in our survey paper. 2 This energy density is comparable to other aluminium alloys for example, Al-33.3wt%Cu at 0.716 kWh/L or Al-12.5wt%Si at 0.708 kWh/L.…”

“…This value is within experimental uncertainty of past measurements 10 but considerably lower than predictions from CALPHAD. 2 The heat capacity of Al-25% Cu-6% Si (wt%) was determined in the solid and liquid states. The data are plotted in Figure 4.…”

“…mPCMs have exceptional thermal conductivity and diffusivity when compared to other common thermal storage materials such as molten salts, paraffins and thermal oils. 2 Pure or eutectic composition mPCMs are preferred over other compositions due to their ideally isothermal melting behaviour. This provides higher cycling stability with minimal phase separation and provides a large proportion of the stored heat at a single temperature, simplifying heat transfer system design.…”

“…Our group at the German Aerospace Centre (DLR) has been investigating Al-based alloys for vehicle applications since 2016. 3 The binary eutectic Al-12.7 wt% Si has been previously investigated with a melting temperature of 577 C. [4][5][6][7] The ternary Al-Cu-Si system has been selected as it has comparable thermal properties to the binary Al-Si with a lower melting temperature of about 522 C. 2 Additionally, this ternary system has showed superior corrosion resistance compared to Al-Cu and Al-Si alloys. 8 Our previous findings show the Al-25.4% Cu-6.1% Si (wt%) (rounded to Al-25% Cu-6% Si [wt%] in the rest of the article) eutectic to be optimal in energy density (both gravimetric and volumetric) and in cost per kWh of latent heat for the temperature range 508 C to 548 C. 2 Given its apparent optimal properties for a temperature range relevant to many applications, the thermal properties and compatibility of the eutectic should be determined to enable implementation.…”

“…Thermal diffusivity and conductivity are material properties characterising the rate at which heat can move within a solid or static liquid material. mPCMs have exceptional thermal conductivity and diffusivity when compared to other common thermal storage materials such as molten salts, paraffins and thermal oils 2 . Pure or eutectic composition mPCMs are preferred over other compositions due to their ideally isothermal melting behaviour.…”