Experimental Research of the Heat Storage Performance of a Magnesium Nitrate Hexahydrate-Based Phase Change Material for Building Heating

Abstract

Phase change heat storage material is a preferred material in solar building heating or off-peak electric-heat storage heating technology and is the research focus. A compact phase change thermal storage device has been designed and experimentally studied for improving heating system load in this work. A new type, magnesium nitrate hexahydrate-based phase change material has been studied to improve the cooling degree and crystallization difficulty. The focus of this study is on the heat charging and discharging characteristics of this new phase change material. The heat storage device has two groups of coils, the inner side which carries water and the outer side which is the phase change material. A testing system was built up to value the thermal cycling performance of the heat storage device. The measurement data include phase change material temperature field, water inlet and water outlet mean temperature, heat charging and heat discharging depth, and flow rates over the operating period. The results show the phase change material has a quick response with the operating temperature range of 20–99 °C. Its latent heat is 151.3 J/g at 91.8 °C. The heat storage density of this phase change material is about 420 MJ/m3. The thermal performance degradation is about 1.8% after 800 operation cycles. The phase change thermal storage device shows flexibility and a great potential to improve the capacity and economy of heating systems.

The Potential Environmental and Social Influence of the Inorganic Salt Hydrates Used as a Phase Change Material for Thermal Energy Storage in Solar Installations

“…Despite the extensive literature on salt hydrates used as PCM materials in solar installations, little is known about the potential environmental effects of their use. Researchers usually only indicate that the environmental aspect is important [13][14][15][16], but there are no detailed studies. The present authors did not find any work that would analyze the technical, economic, environmental, and social aspects in the context of the use of non-organic salt hydrates for applications in solar installations.…”