Light absorptive polymeric form-stable composite phase change material for thermal storage

Light absorptive polymeric form-stable composite phase change tablet (RGO-PARB/MA) was prepared by dip-coating myristic acid (MA) tablets into layers of polymer coating solution with reduced graphene oxide (RGO). RGO serves as light absorptive material to harvest sunlight and converts it to thermal energy to be stored in PCM. Ultraviolet (UV)-Visible absorption analysis showed that RGO absorbs UV and visible light at the absorption peak of 255 nm. In this study, a new in-house experimental setup was also developed to quantitatively measure stored heat energy, solar energy conversion, and storage efficiency in the outdoor environment. RGO-PARB/MA tablet with 1.5 wt% RGO loading had the highest amount of stored heat energy which was 48.91% higher than tablet without RGO. The average solar energy conversion and storage efficiency of 1.5 wt% RGO-PARB/MA tablet was about 21%. The melting temperature and latent heat of 1.5 wt% RGO-PARB/MA tablet were 54.79 ± 0.07 °C and 119.91 ± 6.67 J/g, respectively. Thermal cycle test shows that the composite phase change material has good thermal durability, withstanding up to 1000 thermal cycles (2.7 years) with changes in thermal properties less than 2%.