Study On The Heat Storage And Exothermic Performance Of Interseasonal Phase Change Thermal Storage Tank

With the development of society in recent years,the problems of energy shortage and environmental pollution have attracted more and more attention.The use of clean energy not only reduces environmental pollution,but also relieves the stress of energy stress.Because of its infinity and universality,solar energy has been paid more and more attention to,but the traditional water storage tank is not ideal for solar energy utilization,and has the disadvantages of large size,low heat storage efficiency and low economy.Improving the heat exchange efficiency of heat storage tanks can improve the utilization of solar energy.In order to improve the heat transfer performance of the heat storage tank,this paper proposes a phase change storage tank which combines phase change materials with traditional heat storage tank,and focuses on the storage and heat transfer performance of the heat storage tank with different operating conditions and different structure of phase change storage unit.Based on enthalpy method and solidification and melting theory,the phase change heat storage method should be used in the phase change heat storage tank.The physical model and mathematical model of phase change heat storage tank are established,the heat transfer analysis of cuboid phase change heat storage unit is carried out,and the changes of temperature,velocity and other parameters affecting the heat storage process are studied.With the increase of import temperature,the melting rate of phase transition materials increases correspondingly,and the time needed for complete melting gradually decreases.Increasing the inlet velocity can shorten the melting time of phase transition materials.In addition,the cuboid plus groove phase change heat storage unit was set up and compared and analyzed with the original structure,the number of grooves and the role of groove size in the heat storage process were studied.The results show that the heat storage and heat transfer of the two structures are basically the same,and the addition of the groove makes the new heat storage structure better than the original one.Under the same heat storage volume,the heat transfer effect of the fluted heat storage unit is better,the time is short and fast.It is possible that the increase of the fluted heat transfer area leads to the increase of the fluted heat transfer area,and also increases the disturbance of the internal fluid and strengthens the heat transfer.The heat storage of phase transition units with three different grooves is analyzed under the condition that the heat storage volume is the same,and the melting time decreases gradually with the increase of the grooves.The effect of different groove shape on heat transfer effect was analyzed.When the groove side length ratio is 1: 2,the melting time of phase transition material is the shortest,which is 22.3% shorter.The phase-change heat accumulator studied in this paper has important reference value for improving solar energy utilization rate and optimizing heat accumulator.