Thermal property study of fatty acid mixture as bio-phase change material for solar thermal energy storage usage in domestic hot water application

Abstract

• Thermal property study of Bio-PCM OM55 using TGA/DTA, TCA, and DSC. • T-history method for bulk Bio-PCM quantification and cooling rate curve used to know the transition range. • Effects of cooling rate and thermal mass on supercooling. • Determination of isothermal enthalpy gives the actual enthalpy of the PCM material for proper storage design. • Comparison between conventional DSC, Bulk sample T-history results and the supplier’s data. For the correct design, simulation and specific application of the latent heat thermal energy storage (LHTES) system, detailed evaluation of phase change material (PCM) properties are essential. Present study aims to analyze the thermal and volume dependent behavior of available organic Bio-PCM OM55, using conventional thermal gravimetric analyzer (TGA), thermal constant analyzer (TCA), differential scanning calorimeter (DSC) and in-house T-history method (THM). Execution of the mentioned thermal analysis outcome with significant information of OM55. TGA shows that OM55 is thermally stable within the operating temperature 45–60 °C, because the maximum permissible degradation temperature 154.6 °C is much higher than operating temperature range. The OM55 has considerable thermal conductivity compared to the existing PCM, which is already used in domestic solar water heating (DSWH) applications. The evaluation of transition temperature, isothermal enthalpy, and specific heat by THM are well compared with the DSC analysis. Comparison of DSC and THM analysis showed that the behavior of OM55 is volume independent. The overall study concluded that OM55 is a potential Bio-PCM. However, for the optimum amount of energy storage and discharge in OM55, it is recommended to operate the LHTES unit over a temperature range between 46–59 °C for domestic hot water application.