| Globally,the installed capacity of new energy,mainly represented by wind energy and solar energy,has been developing rapidly at an average annual growth rate of 30%for many years.Due to the inherent instability and intermittent of wind power and solar power generation,the grid connection of wind power and photovoltaic power is poor.If large-scale integration into the power grid will threaten the safe and stable operation of the power grid,large-scale energy storage technology coupling with new energy power generation technology has become a research hotspot.In this paper,the aluminum-silicon alloy phase change heat storage material is selected as the research object,and the induction heating melting process is numerically simulated by the finite element analysis method.The results show that when using a crucible with low conductivity,the electromagnetic loss,that is,the heating power,is basically concentrated at the aluminum-silicon alloy,and the presence or absence of splitting has basically no effect on the electromagnetic loss of the aluminum-silicon alloy.When the crucible with high conductivity is used,the electromagnetic loss of the crucible will rise sharply.When the crucible conductivity increases from 3000 S/m to3×10~7 S/m,the electromagnetic loss of the crucible increases from 100 W to 130 k W.It is extremely disadvantageous for energy storage,so for electromagnetic induction energy storage crucibles,low-conductivity crucibles without splitting should be used.Through the liquid phase distribution cloud diagram of the melting process,it can be known that the molten alloy is affected by natural convection,making the upper half of the alloy melts faster than the lower half,and the upper and lower parts are asymmetry.In order to couple the aluminum-silicon heat storage system with the power plant and undertake part of the power generation of the power plant,a phase-change heat storage and exchange device was designed,and the two-dimensional cross-section of a single heat storage and exchange device was used for numerical simulation to study its heat transfer performance.The results show that the temperature of the liquid aluminum-silicon alloy near the pipe entrance and the elbow drops faster and solidifies faster.When the inlet flow velocity increases from 0.05 m/s to 0.07 m/s and 0.1 m/s,the time of the overall solidification has been shortened from 18800 s to 16600 s and14600 s,respectively,and the average maximum outlet temperature of the heat transfer fluid has been reduced from 298°C to 289°C and 280°C,respectively.When the demand of the coupled power plant cannot be met by heating through a single pipeline,the temperature of the heat transfer fluid can be further increased by heating in series with the pipeline.EBSILON is used to model the thermal system of 600 MW supercritical unit and heat storage device coupled with different parts of the power plant,including coupled reheating,coupled low-intake,coupled first-level high-heat heater,and coupled second-level high heater.The results show that all the four coupling methods can improve the efficiency of the power plant.With the increase of the coupling flow,the efficiency of the other three coupling methods decrease gradually,except for the low-incoming coupling method.As the power generation decreases from 600 MW to 360 MW,the efficiency of the coupled reheat section continues to increase,while the efficiency of the coupled primary heating section and the coupled secondary heating section continues to decrease. |
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