Experimental Investigations On Heat Transfer Coefficient And Stability Of Supercooled Sodium Acetate Trihydrate

With the continuous development of social economy,the energy crisis has become increasingly prominent.With fossil fuels decreasing day by day,solar energy has become an important part of human energy use and has been continuously developed.However,there are still many problems in the application of solar energy.For example,due to natural conditions such as day and night,seasons,geographic latitude,and altitude,as well as the influence of random factors such as sunny,cloudy,cloud,rain,etc.The solar irradiance reaching a certain ground is both intermittent and extremely unstable and low energy density etc.Which increase the difficulty of large-scale application of solar energy.Sodium acetate trihydrate has the following advantages as a potential seasonal heat storage phase change material: the latent energy content is 265J/g;the melt point is 58℃;It is nontoxic,inexpensive and available in large industrial quantities;It has a stable supercool.In the solar energy seasonal heat storage system,use the stable supercool to store energy for a long period.However the problem of phase separation and low heat transfer coefficient of the sodium acetate trihydrate mixture are still exist,which is also the purpose of this paper.In this paper,the relationship between the excitation temperature of the sodium acetate trihydrate solution with a water content of 42% and the height of the different liquid levels was experimentally studied.It was found that the excitation temperature of the sodium acetate trihydrate solution with the same water content increased with the height of the liquid surface;The long-term stability observation of several groups of sodium acetate trihydrate samples with the same water content but different liquid heights showed that there were different degrees of crystal precipitation in the samples;Several different thickener pairs were experimentally studied the stability of sodium acetate trihydrate solution as well as the change of the excitation temperature and enthalpy,and the long-term stability observation experiment and the cyclic experiment of several groups of the same water content and the height of sodium acetate trihydrate added with the thickener were found in the selected Among the thickeners,the effect of CMC on crystallinity of sodium acetate trihydrate is most obvious.A phase change energy storage heat exchanger structure is designed,and the heat transfer coefficient of the trihydrate sodium acetate phase change heat storage system is designed.Theoretical analysis of heat storage capacity.