Abstract:

Nitrate phase change materials are the most widely used phase change materials in solar thermal power generation technology.However,the maximum service temperature of Nitrate phase change materials is only 600 ℃.Therefore,to find a phase change material with large heat capacity,wide temperature range,low heat loss and low price is the focus of current research.According to different mass ratios,nine binary molten salt mixtures were prepared by mixing lithium chloride and sodium chloride.The phase transition temperature and latent heat of phase transition of the nine binary molten salt mixtures in the range of 600 ℃ were studied by differential scanning calorimeter（DSC）.The experiment results showed that since the melting point of sodium chloride was high,when the content of sodium chloride in the binary mixture of lithium chloride and sodium chloride was large,that is,the content of lithium chloride was small,a small amount of lithium chloride could not re-duce the melting point of the mixture below 600 ℃,the mixture could not be melted.Meanwhile,when sodium chloride and lithium chloride were melted,the phase transition temperature of lithium chloride and sodium chloride remained at about 540 ℃ and floated at ±15 ℃.The melting temperature and crystallization temperature of the binary mixture of 90% lithium chloride and 10% sodium chloride were quite different,and the latent heat of phase transformation was relatively high.Therefore,the binary mixed molten salt can be used in the heat transfer and storage technology of solar power generation.

Key words: inorganic phase change materials, binary mixture, chloride salts, phase change latent heat