Ali Yadegari

The main goal of this research is to prepare a phase change material (PCM) with a stable structure using paraffin (as a phase change material), polyethylene (HDPE) and ethylene vinyl acetate (EVA), in such a way that the obtained PCM shows an acceptable flexibility and mechanical strength. This form stable PCM was prepared by mixing method. In order to investigate and improve the performance of PCM, leakage test DSC, TGA and XRD were used. The results of the leakage test showed that the P80E10H10 PCM, which contains 80% paraffin, 10% EVA and 10% HDPE, has the lowest leakage. Also, P80E20H00, which does not contain HDPE, showed the highest leakage. The 100-cycle leakage test showed that after 100 cycles, the presence of both polymers had a good effect on the stability of phase change materials. The results obtained from the DSC test showed that the P80E10H10 sample has the highest melting enthalpy. The melting temperature and crystallization temperature of the samples were also evaluated. The results of the TGA test showed that paraffin and HDPE have one degradation temperature, but ethylene vinyl acetate has two degradation temperatures. Also, the TGA curve showed that LP80E20H00 compound has the highest degradation temperature and SP80E20H00 compound has the lowest degradation temperature. The results obtained from the XRD test showed that the main diffraction peaks of the materials (paraffin, polyethylene, and ethylene vinyl acetate) were consistent. The results showed that there was no change in the crystalline structure of polymers and paraffin due to process conditions. In general, it can be concluded that the manufactured form stable PCM has a favorable performance to be used in energy storage systems.