Solar thermal energy storage based on sodium acetate trihydrate phase change hydrogels with excellent light-to-thermal conversion performance

摘要

Phase change materials (PCMs) play significant roles in solar thermal energy storage. In this work, a novel PCM, light-to-thermal conversion phase change hydrogel (LTPCH) consisting of NaAc center dot 3H(2)O, acrylamide-acrylic acid sodium co-polymer and CuS was prepared using a melt impregnation process. The morphologies, thermal physical properties, light-to-thermal conversion performance and cycling lifetimes of prepared LTPCHs were investigated. A fluid leakage test showed that LTPCH containing 87 wt% NaAc center dot 3H(2)O can keep a solid-gel structure without liquid leakage in the phase change process. Scanning electron microscope micrographs confirmed that LTPCH was structured by near-spherical particles which were mainly composed of NaAc center dot 3H(2)O confined in the three-dimensional polymer networks. Differential scanning calorimeter tests revealed that the melting temperature of LTPCH was 57.1 degrees C, close to that of NaAc center dot 3H(2)O, and its latent heat was as high as 202.4 J/g. The light-to-thermal conversion experiments indicated that CuS was an effective photon capturer and it can provide LTPCH with an excellent light-to thermal conversion efficiency of 87.1%. After 300 melting/freezing cycles, LTPCHs maintained good thermal physical properties and high light-to-thermal conversion efficiency, and therefore showed great potential for use in solar thermal energy storage. (C) 2018 Elsevier Ltd. All rights reserved.