| Since the energy crisis of the 1970s,research about phase change energy storage has rapidly emerged in developed countries.Its research and application areas include materials science,solar energy,engineering thermal physics,air conditioning and heating,and industrial waste heat utilization.The theory and application of phase-change energy storage are the directions of disciplines that grow in many areas of disciplines and rapidly developing.With the rapid economic developing,the peak-to-valley difference in electricity usage in China has become increasingly serious.At the same time,the pollution problems caused by winter heating in cities have become more serious.In order to improve these problems,the use of electricity loads has been adjusted and the heating energy structure for winter heating has been adjusted.It is necessary to further study heat storage technology and develop products by using heat storage technology.A new type of composite stereotype phase change heat exchanger was designed in this paper.By using sol-gel method and vacuum leaching infiltration method,the PEG/SiO2/EG composite shape-stabilized phase change material was prepared.The material has appropriate phase change temperature and latent heat value.And it's non-toxic and non-polluting,and no leakage occurs in the phase changing.The physical model and mathematical model of the phase change heat exchanger was established according to the basic theory of phase change heat transfer and phase change device design criteria.The heat transfer performance and regularity of the heat exchanger were simulated and solved by the grid division software GAMBIT and CFD software FLUENT.A stereotyped phase change heat exchanger experimental bench mentioned above was built.Then experimental results can be used to verify the reliability of the model,and to test the effect of the PEG/SiO2/EG shape-stabilized phase change material.A small stereotyped phase change heat exchanger is designed to compare the tube type,ring ribs,longitudinal ribs and steel column heat exchangers.The results show that the surface ring ribbed heat exchanger has the best performance,and the influence of the inlet temperature and inlet velocity on the performance of the heat exchanger is studied.The orthogonal test of four factors?rib height,rib width,rib spacing and tube?of a ring finalized phase change heat exchanger was designed and analyzed by multiple factor variance to find out the significant factors.According to the above research,the key and difficult points in the design of the type phase change heat exchanger are summarized.Finally,a new type of type phase change heat exchanger is designed.The heat storage and exothermic efficiency are both about 80%,and can be"modularized"free splicing.Finally,the application and operation methods of the new type of phase change heat exchanger are briefly introduced.To summarize,a new type of composite stereotype phase change heat exchanger was designed in this paper can perform heat storage and heat release at the same time.It is light and compact.It easy to encapsulate and can achieve modular production.The phase change heater can be applied to solar heating and home heating end.It has wide range of applications,energy saving and environmental protection.The results of research can provide references for the optimization of such heat exchangers in the future,which have important theoretical value and practical engineering significance. |
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