Study on thermal conductivity of the candle making wax (CMW) using nano - TiO2 particles for thermal energy storage applications

Abstract

Thermal energy storage becomes a greater challenge in thermal conversion systems such as solar thermal systems. The energy demand and supply may not be matched at the most point of time, hence requires efficient thermal energy storage. Candle Making Wax (CMW) is one among the potential material to store energy by means of changing its phase. Still, they are suffering with poor thermal conductivity. This paper addresses this problem by diffusing a suitable nanoparticle in CMW. Nano-TiO2 particles have been used as enhancer in CMW in different proportions viz., 0 vol.%, 0.5 vol.%, 1.0 vol.%, 1.5 vol.% and 2.0 vol.%. These five samples were inspected using Fourier Transform Infrared Spectrometer (FT-IR) to verify their chemical stability. Thermal conductivity of all the samples were initially calculated using different analytical models and later, they were experimentally determined with the help of thermal properties analyzer. The results proved that the thermal conductivity can be improved substantially by dissolving the nano-TiO2 in CMW. Thermal conductivity escalates with the increased vol.% of nanoparticles. However, values predicted through the analytical models showed the linear improvement, whereas the experimental values were not exactly linear and their slope becomes less at the higher vol.% of nanoparticles. It was observed that the solid state thermal conductivity was more compared to their liquid state, Also, it was noticed that the experimentally measured values were relatively higher than the values obtained through the analytical models and variation was high at higher vol.% of nanoparticles.Thermal energy storage becomes a greater challenge in thermal conversion systems such as solar thermal systems. The energy demand and supply may not be matched at the most point of time, hence requires efficient thermal energy storage. Candle Making Wax (CMW) is one among the potential material to store energy by means of changing its phase. Still, they are suffering with poor thermal conductivity. This paper addresses this problem by diffusing a suitable nanoparticle in CMW. Nano-TiO2 particles have been used as enhancer in CMW in different proportions viz., 0 vol.%, 0.5 vol.%, 1.0 vol.%, 1.5 vol.% and 2.0 vol.%. These five samples were inspected using Fourier Transform Infrared Spectrometer (FT-IR) to verify their chemical stability. Thermal conductivity of all the samples were initially calculated using different analytical models and later, they were experimentally determined with the help of thermal properties analyzer. The results proved that the thermal conductivity can be improved substantially by...