Experimental investigation of photothermal properties of phase change material enhanced by Zn–TiN binary nanoparticles

Abstract

By the widely application in solar energy conversion systems for phase change materials (PCM), the photothermal properties of PCM are important for the efficiency of systems. As a typical PCM, the applications of paraffin in solar utilization are limited by it poor photothermal properties. In order to improve the photothermal performance of pure PCM, Zn–TiN binary nanoparticles are chosen for the enhancement in the present work. Furthermore, the photothermal properties of Zn–TiN binary nanoparticles enhanced phase change material (NePCM) with various volume fraction are evaluated by thermal properties, capacity of solar energy absorbed, and photothermal conversion performance. In addition, the stability of NePCM effected by dispersants and the temperature variation regularity of samples effected by solar radiation intensity and temperature monitoring locations are also studied. As the results: CTAB is a suitable dispersant for the NePCM. Under the same concentration (0.001 vol%), Zn–TiN binary nanoparticles can improve the solar absorption capacity of pure PCM significantly which enhanced almost 8 times. However, due to the aggregation of nanoparticles, the efficiency of photothermal conversion decreases with the increase of volume fraction, therefore, 0.001 vol% Zn–TiN binary NePCM gives the maximum efficiency of 22%, that is twice than that of the pure PCM. Photothermal conversion performance improved with the increase of intensity of solar radiation. Under the intensity of 600 W/m 2 , the peak temperature of 0.01 vol% Zn–TiN binary NePCM is 62.57 °C which appears in the center of the sample. • A new binary NePCM consisted by Zn, TiN nanoparticles and PCM is prepared. • Photothermal properties of binary NePCM are explored by mathematical and experimental method. • A system for researching photothermal conversion capacity is set up. • The influencing factors of photothermal conversion capacity of Zn–TiN NePCM are researched.