Development of new nano-enhanced phase change materials (NEPCM) to improve energy efficiency in buildings: Lab-scale characterization

Abstract

Fatty acids are promising organic phase change materials (PCMs) for thermal energy storage (TES) in buildings because of their high storage capacity, non-toxic nature and little subcooling. Their phase change temperatures make them suitable for heating, ventilating and air conditioning (HVAC) applications in the building sector. However, one of their main drawbacks is their poor thermal conductivity which limits their application. In the present study two fatty acids within the building application temperature range, capric acid (CA) and capric-myristic acid (CA-MA) eutectic mixture, were nano-enhanced throughout silicon dioxide nanoparticles (nSiO2) addition (0.5 wt.%, 1.0 wt.% and 1.5 wt.%). Main properties of the nano-enhanced phase change materials (NEPCM) obtained were characterized by means of differential scanning calorimetry (DSC), Hot wire technique, Fourier transformed infrared (FT-IR) spectroscopy, thermogravimetric analyses (TGA), scanning electron microscopy (SEM), and rheological measurements. Furthermore, their long-term performance was evaluated after 2000 cycles by means of cycling stability tests. The NEPCM obtained showed high thermal conductivity and specific heat capacity. Additionally, both are thermally stable within their working temperature range and ensure a long-term performance.