Performance enhancement of a thermal energy storage system using shape-stabilized LDPE/hexadecane/SEBS composite PCMs by copper oxide addition.

Thermal Energy Storage (TES) technologies based on Phase Change Materials (PCMs) with small temperature differences have effectively promoted the development of clean and renewable energy. The organic phase change materials are most commonly used in latent heat TES (LHTES). Nevertheless, the trend of this type of material limits their applications because of their low thermal conductivities and liquid leakage over the phase transition process. Copper oxide (CuO) microparticles served as an additive to enhance thermal performance and a series of shape-stabilized composite PCMs (SSPCMs) were prepared by physical impregnation. The composites were characterized for their micro-morphology, chemical structure, thermal degradation stability and thermal energy storage performance with the aid of SEM, FT-IR, ATG, infrared thermography (IRT) and DSC, respectively. To obtain the maximally efficient energy storage capacity, the mass fraction of Hex (PCM) was found to be 75%, with a good form stability, which surmounts almost all mass fraction values reported in the literature. The ATG curves of all PCM composites revealed that addition of CuO has increased the onset degradation temperature and the maximum weight loss temperature. During the heating and cooling processes, leakage and impairment of the composite PCM were not detected. Significant enhancement in melting time and larger heat storage capacity were observed when 15% CuO was added to the SSPCM as revealed by IRT. The DSC results of the SSPCM composite indicated that the presence of CuO microparticles in PCM composites reduces the supercooling effect during the phase change process and increases the energy storage/release capacity with suitable phase change temperatures for building TES applications.