Experimental study on a new thermal storage tank with an embedded bionic skeleton based on inorganic hydrated salt phase change material

Abstract

Energy storage technology is an important mean to calm down the fluctuation of renewable energy and promote the research of energy storage technology to become a strong backing for the smooth and orderly development of renewable energy. Inorganic hydrated salt phase change materials, as an important material for phase change energy storage technology, have the advantages of high thermal storage density, high thermal conductivity, moderate phase change temperature, low cost, and easy availability. However, in practice, inorganic salt materials have problems with lose of crystal water, which seriously affect the service life of phase change thermal storage devices. It is urgent to prevent the loss of crystal water. Herein, potassium aluminum sulphate dodecahydrate (Alum) was used as a typical hydrated salt phase change material. A new heat storage tank was designed. The lid of the tank has a condensation coil that allows the crystal water to return to the material more quickly. At the same time, the interior of the thermal storage tank is embedded with a bionic skeleton, which allows the crystalline water to return uniformly to the phase change material at different depths. It was found that the heat storage capacity of the materials at different depths of the new box was the same, which also meant that the crystal water returned evenly to the materials at different depths. After 500 cycles, the new heat storage box had lost only 7.9 % of its heat storage capacity. This study is expected to be extended to hydrated salt phase change materials to prolong the service life of the materials and give full play to the advantages of hydrated salt phase change materials.