Preparation and thermophysical properties of low temperature composite phase change material octanoic-lauric acid/expanded graphite

Abstract

A new composite phase change material (PCM) was developed with octanoic acid and lauric acid as a base fluid and expanded graphite (OA-LA/EG) as matrix. The OA-LA/EG base fluid was determined with mass ratio 81:19 and the optimal ratio of EG was 7 wt%. The transition temperature and latent heat of OA-LA/EG were measured by differential scanning calorimetry (DSC). The thermal conductivity of OA-LA/EG was measured by Hot Disk thermal constant analyzer. In addition, the cool storage and discharge cycle tests were carried out for 100 times to validate the stability of OA-LA/EG. The experimental results show that, the phase transition temperature of OA-LA/EG is 3.6 °C and the latent heat of phase change is 132.8 J·g−1. The thermal conductivity of OA-LA/EG is 1.275 W·(m·K)−1 which is 2.8 times higher than that of OA-LA. The phase change temperature, latent heat and thermal conductivity demonstrated good reliability. The composite PCM developed has great prospect in the practical application to medical refrigeration transportation system and air conditioning cold storage system with temperature range of 2–8 °C.