Study on inorganic PCMs modification utilized in building environment for energy conservation

Abstract

ABSTRACT Many inorganic phase change materials (PCMs) are able to be adopted in different fields for reducing energy consumption. In building constructions, PCMs, such as CaCl2·6H2O and Na2SO4·10H2O, have been studied on indoor temperature adjustment. In this paper, CaCl2·6H2O is an aimed material for researches which are in order to make it possible in building energy conservation. Supercooling was a negative property of inorganic PCMs, and it has limited wide utilization for decades due to the decay of its efficiency on energy exchange. Different dosages of nucleating additives were designed for supercooling reduction, and 0.8wt% nano-SiO2 could reduce the supercooling of self-made CaCl2·6H2O to 0.2°C. Xanthan gum was used as additive thickeners to improve durability and reliability of inorganic PCMs, and 3wt% additive dosages could keep homogeneity of melting CaCl2·6H2O. Adding thickeners did not create negative effects on nucleating process of CaCl2·6H2O. Combining 0.8wt% nano-SiO2 and 3wt% xanthan gum with self-made CaCl2·6H2O, the supercooling reduction was controlled on around 0.3°C after 500 temperature cycle times.