Novel composite phase change materials with enhancement of light-thermal conversion, thermal conductivity and thermal storage capacity

Abstract Composite phase change materials (CPCMs) play a key role in solar energy conversion and storage. However, it is difficult to efficiently utilize solar energy due to their inherent low thermal conductivity, low light absorption and the usual competitive nature between thermal conductivity and latent heat. In this work, novel CPCMs were developed by using TiO2-TiC-C loaded expanded vermiculite (EVT) as a supporting matrix and lauric-myristic-stearic eutectic mixture (LA-MA-SA) as a PCM. The EVT was further acidized (EVTa) to enhance its PCM absorbability. Owing to the high thermal conductive and light absorption nature of TiO2-TiC-C nanocomposite, the prepared CPCMs exhibit efficient light-thermal energy conversion. The thermal conductivities of LA-MA-SA/EVT and LA-MA-SA/EVTa were 0.694 and 0.676 W/(m K), respectively. And the PCM content in LA-MA-SA/EVT and LA-MA-SA/EVTa were 64.5 and 70.6 wt%, respectively. Moreover, the feasibility of CPCM being a water heating source was experimentally confirmed. These novel CPCMs have good application prospect in low temperature solar-thermal installations, such as temperature adaptable greenhouse and water heating system.