The Experimental Study On Crystallization Temperature And Stability Of Supercooled Sodium Acetate Hydrate Solution

The development of economy and society is more and more restricted by the energy crisis.So solar energy,as the new energy has received extensive attention.At present,the application of solar energy is mainly in the use of solar photo-thermal.But solar energy by region distribution,diurnal cycles,and difference of the changing seasons restricts the sustainability and continuity of its application.Solar energy peak load shifting depends on the heat storage and release.In sensible heat,latent heat and chemical heat storage,the efficiency of latent heat thermal storage is the highest.The solid-liquid phase transition temperature of the phase change heat storage material sodium acetate trihydrate is 58 0C.As with other inorganic hydrous salt,the existence of supercooling and phase separation phenomena during phase transition,the use and thermal performance of the heat storage unit are severely restricted by that.If the characteristics of the thermal storage materials in seasonal heat storage and other long-term storage heat can be used,the heat preservation of long-term stability in the supercooled state.Until the use of the time to stimulate the crystallization,release the heat,there will be a good prospect in the long term storage applications.In order to find the long-term stability of the supercooled state of sodium acetate hydrate,we configuration different water acetic acid sodium salt hydrate based of sodium acetate trihydrate,exploring them in supercooled state of nature.Then we make it use in long term storage enthusiasm,to solve the problem of solar energy because of time,space,and other factors uneven distribution.In this paper,the crystallization temperature and the stability of sodium acetate hydrate supercooled solution are studied by experiments.The liquid height of 4cm,water content of 40%,45%,50%,and 55%of the solution,the crystallization temperature decreases with the increase of water content.When the water content is 45%,the liquid level height of 3 cm,4cm,5cm,and 6cm,the crystallization temperature of solution increases with the increase of the height of the liquid level.Solution with water content of 40%,45%,50%,and 55%,the liquid height are 3 cm,4cm,5cm,and 6cm.The crystallization temperature of hydrate decreases with the increase of water content,and increases with the increase of the liquid level.The lowest of the crystallization temperature in these 16 kinds of hydrate is nearly-20 degrees Celsius,but the highest is only below 3 degrees Celsius,far below room temperature.Experiments with 40%of the water samples,for example,through the comparison of the glass bottle and the iron bottle found crystallization temperature and the bottle diameter no relationship,and with the material of the bottle.Through the experiment,it is found that the crystallization temperature increases with the decrease of cooling rate.When the thickness of the insulation layer increases to 3 layers(9cm),the crystallization temperature is only 10 degrees Celsius,The long-term stability of the solution do study.In containing water 41%,42%,43%and 44%,45%of five groups of samples,regardless of the liquid level height is 3cm or 6cm,in addition to containing 45%of water samples,obvious phase separation.