Research Article

Investigation of In–48Sn as a phase change material candidate for thermal storage applications

¹ Solar Thermal Energy Research Group, School of Mathematical and Physical Sciences, North-West University, Mafikeng, South Africa
² Department of Mathematics, Science and Sports Education, University of Namibia, Ongwendiva, Namibia

^* e-mail: ashmore.mawire@nwu.ac.za

Received: 27 February 2017
Received in final form: 4 July 2017
Accepted: 27 July 2017

Abstract

Latent heat storage systems provide large thermal storage densities for solar energy storage for various domestic and industrial applications. In–48Sn, an alloy of indium and tin a lead-free solder is investigated as a phase change material (PCM) in latent heat storage systems for heating applications. Results obtained from differential scanning calorimetry indicate that the alloy is useful in storing sensible heat beyond its melting temperature as it exhibits very little decomposition up to 400 °C. Though In–48Sn possesses a low latent heat of fusion, its high density allows for a larger thermal storage mass. The behaviour of In–48Sn in a 50 mm aluminium spherical capsule during charging and discharging cycles is investigated using sunflower oil as the heat transfer fluid (HTF) at flow rates of 3, 6, 9 and 12 ml/s. The influence of the charging temperature on the charging characteristics of the encapsulated PCM is also investigated. The average charging and discharging rates of the encapsulated PCM show an increase with an increase in the HTF flow rate. The HTF temperature determines the maximum temperature attained by the PCM and thus the total energy stored by the encapsulated PCM. In–48Sn shows good potential as a PCM in a spherical aluminium capsule for packed bed domestic heat storage systems.