Experimental investigation of Mg-Zn-Al metal alloys for latent heat storage application

Abstract

In this paper the use of metallic alloys is proposed as high thermal conductivity phase change materials (PCM) for thermal energy storage (TES). The high thermal conductivity of the proposed metallic PCMs is around two orders of magnitude higher than the one of materials (molten salt) commonly used on TES applications. This would present great benefits in several applications frames from the concentrated solar power (CSP) to industrial heat recovery. In this work, three different alloys, with different Al content, have been selected from the Mg-rich corner of Mg-Zn-Al ternary phase diagram with general formulas Mg71Zn28.9Al0.1, Mg70Zn24.9Al5.1 and Mg70Zn24.4Al5.6. The first and third materials correspond to quasi-peritectic compositions and the second material corresponds to a eutectic composition. The eutectic compositions, in general, are considered more suitable as PCMs for TES application due to their long-term stability under charging discharging cycles. The two quasi-peritectic compositions have been selected to investigate the influence of the chemical composition changes on the thermophysical properties and consequently to study their potentiality regarding the energy storage density factor.In this work, a complete structural and thermophysical characterization of the selected metal alloys has been carried out in order to obtain the driving parameters for latent heat storage applications. In general, the obtained results confirm the suitability of the investigated metals alloys as high thermal conductivity phase change materials for latent heat energy storage.