Preparation and Characterization of Myristic-palmitic Acid/Nano Silicon Dioxide/Nano Silicon Carbide Composite Phase Change Materials for Air Conditioning Condensation Heat Recovery System

Abstract

In this research, myristic-palmitic acid(MA-PA)/ nano silicon dioxide(nano-SiO2) was modified by adding nano silicon carbide(nano-SiC) with high thermal conductivity. The MA-PA/nano-SiO2 composite phase change material (PCM) was prepared by impregnating the MA-PA eutectic mixture as PCM into nano-SiO2 as supporting material. Nano- SiC was added to improve the thermal conductivity of MA-PA/nano-SiO2 composite PCM. Leakage experiments demonstrated that the optimal percentage of MA-PA eutectic mixture adsorbed in nano-SiO2 was 62wt%. The results of thermal conductivity meter measurement showed that the heat transfer coefficient of the MA-PA/nano-SiO2 /nano- SiC composite PCM with 9wt% nano-SiC was 0.776 W/(mK), which increased by 83.02% compared with MA-PA/nano-SiO2 composite PCM. The composite PCM melted at 42.96°C with a latent heat of 88.37J/g and solidified at 44.12°C with a latent heat of 82.45J/g, which were examined by using the differential scanning calorimeter. Thermogravimetric analyzer test results find that composite PCMs had good thermal stability in the working temperature range. Based on the above results, it was known that modified MA-PA/nano-SiO2 /nano- SiC composite PCMs had better thermodynamic properties and were widely applied future in air conditioning condensation heat recovery systems.