Development of Eutectic Phase Change Materials for Solar Thermal Energy Storage

This paper presents the findings on preparation and thermal analysis of binary eutectic mixture of polyethylene glycol 2000 and 6000. Their measured latent heat are 165.3 J/g and 220 J/g respectively. Eutectic mixtures of these materials were prepared by weight percentage composition with an increment of 10% i.e. compositions of PEG 2000 : PEG 6000 with 0:100, 10:90, 20:80 and so on till 100:0 were prepared. The thermal properties, melting temperatures and latent heats of fusion of these mixtures were measured by DSC analysis. The eutectic mixture with 50:50 composition was kept in a thermal cycling test rig to perform an accelerated thermal cycle test up to 1500 cycles. The melting temperature and latent heat of fusion of this thermally cycled mixture were obtained by DSC analysis on 0 th , 100 th , 500 th , 1000 th and 1500 th cycle. There was a drop of 1.9 °C in the melting temperature and 8% degradation in latent heat of fusion was observed in comparison to 0 th cycle. Considering these values it can be deduced that the eutectic mixture is thermally stable.