Carbon nanotube/carbon foam thermal-bridge enhancing solar energy conversion and storage of phase change materials

Abstract

Combining solar energy conversion with latent heat storage based on phase change materials (PCMs) has offered a promising way for expanding solar energy utilization. However, the application of PCMs for solar heat utilization is greatly limited by low thermal conductivity and poor sunlight absorption capacity. Carbon foam (CF) has excellent sunlight absorption properties, and carbon nanotube (CNT) have good thermal conductivity. In this study, CF/CNT porous material was prepared by self-assembly thermal-bridge between CF and CNT. CF/CNT was employed to a porous matrix for the encapsulation of octadecanol (OC), and then a composite photothermal PCM (CF/CNT/OC) was successfully fabricated. Compared with pure OC, the CF/CNT/OC has superior thermal conductivity capacity and excellent photothermal conversion performance. The thermal conductivity of CF/CNT/OC89 reached 1.31 W m⁻¹ K⁻¹, and the photothermal conversion efficiency was 82.6 %. Meanwhile, the melting enthalpy of CF/CNT/OC98 reached up to 275.8 kJ∙kg⁻¹, exhibiting the excellent thermal storage properties. This functional composite PCM has broad application prospects in solar energy capture and storage, building energy saving and so on.