A form-stable photothermal conversion phase change material based on CuS for efficient solar energy collection

Copper sulfide (CuS) has been considered as an excellent photothermal conversion material in solar energy applications. The integration of CuS into phase change material (PCM) enables the unification of photothermal conversion and thermal energy storage. In this study, to avoid sedimentation of CuS particles in (PW), two kinds of thermoplastic elastomer (TPE) are simultaneously used as supporting materials to fabricate form-stable PCM. The form-stable, thermal properties, and photothermal effect of PW/TPE/CuS composite PCMs are analyzed. The results show that the shape stability of composite PCM improves with the increase of the content of TPE. The TPE with 20 wt% concentration can prevent the leakage of PCM and sedimentation of CuS particles, and the composite PCM also exhibits excellent flexibility. The melting latent heat of the composite PCM decreases with the increase of TPE and CuS, and the minimum latent heat is as high as 129.5 J/g. The solar absorption of composite PCM increases with the increase of CuS, and the photothermal conversion efficiency of composite PCM with 15 wt% CuS is calculated as 88.7 %. Furthermore, the composite PCM is employed in a solar water heater. The water temperature can be heated to 67.9 °C, and the composite PCM also has the capacity to decelerate the cooling of water. The water temperature can still maintain above 40 °C after 24:00 p.m. In conclusion, the prepared PW/TPE/CuS composite PCM demonstrates potential for utilization in solar energy storage applications.