Measurement and prediction of liquid-phase density for sugar alcohol phase change materials

The liquid-phase density of phase change material (PCM) is a key thermophysical property to analyze the heat transfer properties of phase change process and the evolution process of phase-change interface. Six sugar alcohol PCMs, which are widely used for medium-temperature heat storage, are selected. Their liquid-phase density data in wide temperature ranges is measured by a thermostatic liquid-phase density measurement instrument. Results show that the variation of liquid-phase density can reach up to 2.43% as the temperature changes by 30°C for six sugar alcohol PCMs. The maximal difference in liquid-phase density of different sugar alcohol PCMs can reach up to 4.62% at the same temperature. Furthermore, the specialized high-precision prediction models of liquid-phase density are constructed for six sugar alcohol PCMs, respectively. A general prediction model of liquid-phase density is also constructed, which is suitable for all the sugar alcohol PCMs. The root mean square relative error of all the specialized prediction models are less than 0.15%, and that of the general prediction model is less than 0.25%.