Experimental Study On Heat Storage And Release Characteristics Of Paraffin-stearic Acid/Expanded Graphite

With the rapid development of economy,China's energy consumption is increasing rapidly.Too rapid energy consumption leads to great pressures on energy supply and has great effect on the environment.The development and utilization of clean energy has become the trend of energy development.Solar energy is a huge energy treasure,which has the characteristics of cleanness,non-pollution and convenient access.But the solar radiation also has the characteristics of rarefaction,discontinuity and instability.Storage energy is one of the best ways to meet the needs of continuously using solar energy in production and in daily life,which is a new energy storage technology based on the phase change materials.Therefore,studying phase change energy storage material is the premise of studying energy storage technology.The research objects of this research are paraffin wax and stearic acid.This research studies the optimum ratio of them and tests the thermophysical parameters of paraffin wax-stearic acid composite phase change material.By matching paraffin wax and stearic acid,it can be concluded that the best ratio is 1:1.Besides,the research shows that as the latent heat storage material,paraffin wax ? stearic acid has the proper phase-transition temperature,higher latent heat of phase change,and none phenomenon of undercooling and chromatography.In addition,it has the advantages of stable performance,nontoxicity,non-corrosiveness and lower price.As the composite phase change material,the shortcoming of paraffin wax ? stearic acid is its low thermal conductivity.In order to strengthen its feasibility in the storage areas,the way of putting additives into paraffin wax and stearic acid can be applied.This research puts expanded graphite into paraffin wax?stearic acid to improve the thermal conductivity.By matching expanded graphite and paraffin wax?stearic acid,it can be concluded that the best ratio is 1:20.At the same time,the thermophysical parameters of paraffin wax-stearic acid composite phase change material is tested.Through a large number of experiments,the heat transfer characteristics of expanded graphite into paraffin wax?stearic acid in melting and solidification are proved.In the melting experiment,this research mainly analyzes the effect of water temperature on the melting process of paraffin wax ? stearic acid and expanded graphite and the temperature variation trend of different testing points under different inlet temperatures.The conclusion is that the higher the inlet temperature,the faster the melting is.In the solidification experiment,this research mainly analyzes the effect of cooling water flow on the cooling process and the temperature variation trend of the different testing points under different inlet flows.It can be concluded that the more the inlet flow,the faster heat release is.According to the phase change heat transfer model,composite phase change heat transfer model of paraffin and stearic acid of expanded graphite is built.Through simulating,the effects of different temperatures and flows on the heat transfer performance of paraffin wax?stearic acid and expanded graphite is analyzed.