Research On The Heat Storage Performance Of Mixed Inorganic Hydrated Salt And Its Phase Change Wall

The consumption of energy is an important driving force for social development.With the development of society,people’s requirements for living standards are getting higher and higher,which leads to the increase of energy consumption.The environmental pollution caused by energy consumption is even more a threat to people’s health.The blue sky without haze has gradually become a luxury.As a developing country,our country has a serious contradiction between people’s growing demand for life and the environmental pollution caused by the rapid development.How to realize the harmonious coexistence of human beings and nature has become a key problem in the development of our country.The development and application of phase change energy storage technology provide an effective way to solve this problem.By adding the phase change material to the building envelope structure,the energy consumption of the building can be effectively reduced,the indoor temperature fluctuation can be reduced,and the comfort of the human body can be improved.There are many kinds of phase change materials.The price of inorganic hydrated salt is low,the latent heat is high and the heat storage density is high.In recent years,inorganic hydrated salt has been paid more and more attention by researchers.In this paper,four kinds of inorganic hydrated salts,sodium sulfate decahydrate,sodium carbonate decahydrate,sodium acetate trihydrate and magnesium sulfate heptahydrate,are used as basic materials.Firstly,the preparation method of binary mixed inorganic hydration salts prepared according to different proportions was studied.Then,the thermal storage performance of the binary mixed inorganic hydrated salts was tested by differential scanning calorimeter,including the phase transition temperature and latent heat.Finally,the feasibility,heat storage capacity and energy saving effect of inorganic hydrated salt shape-stabilized phase change wall are studied.The experimental results show that when the mixed inorganic hydrated salts are prepared by direct heating,the mixed inorganic hydrated salts have thermal weight loss,and the proper amount of deionized water should be added to it to replenish the evaporated water during the preparation process,so that the mixed inorganic hydrated salts can be recrystallized better.Magnesium sulfate heptahydrate mixed with the other three inorganic hydrated salts,respectively,cannot form a good eutectic.The latent heat value of Na₂SO₄·10H₂O-Na₂CO₃·10H₂O mixed inorganic hydrate salts is lower than that of the two components alone,and most of them still have serious problems of undercooling and phase separation.Mixing a small amount of sodium carbonate decahydrate in sodium acetate trihydrate can effectively reduce the undercooling of sodium acetate trihydrate,and its phase change latent heat is still above 250J/g.When the sodium sulfate decahydrate and sodium acetate trihydrate are prepared at a mass ratio of 5:5,the phase change latent heat of the binary mixed inorganic hydrate salt can be up to 297.9 J/g.It is not feasible to add inorganic hydrated salt directly to the middle of the wall by the method of stratified insertion.The heat transfer performance of the phase change wall made by this method is unstable and leakage occurs.After three cycle experiments,the heat storage capacity of the phase change wall is basically lost.The heat transfer performance of inorganic hydrated salt shape-stabilized phase change wall is stable,the heat storage capacity is good and the energy saving effect is obvious.After repeated cycle experiments,there is no obvious attenuation.When two layers of shape-stabilized phase change materials are inserted into the wall,the effect of heat storage is better,the temperature fluctuation is smaller and the energy saving effect is better.