Dynamic Adaptive Characteristics And Regeneration Optimization Strategy Of Solid Phase Change Energy Storage Wall

At present,phase change materials(PCM)are widely used in building envelope to improve the thermal performance of wall and indoor thermal comfort,but there is little research on the regeneration of phase change materials in phase change energy storage wall.In this paper,the melting mechanism of phase change materials in phase change energy storage wall is analyzed by means of numerical simulation and experimental test,and the regeneration optimization strategy of phase change materials by night ventilation and capillary radiation air conditioning is put forward.The main work contents are as follows:The phase change wall test-bed is designed and built.Taking the daily comprehensive temperature in Hangzhou in August as the boundary condition,the phase change wall simulation model is established.The simulation results are compared with the experimental results.The maximum error rate of the inner wall temperature is 0.17%,and the average error rate is 0.03%,both of which are less than5%,indicating that the numerical simulation model is reasonable and effective.Considering the influence of outdoor dry bulb temperature and radiation intensity,taking the summer standard day comprehensive temperature of typical city Hangzhou in hot summer and cold winter area as the boundary condition and considering the influence of natural convection,the dynamic heat transfer characteristics of energy storage and release of ordinary phase change wall are analyzed.The results show that the ordinary wall with PCM interlayer only on the west wall of the building has poor thermal insulation effect.When the temperature difference between the two sides of the phase change layer is 8 ℃,the melting speed of phase change materials is faster,and the melting rate increases with the increase of ste number.The melting rate of 70%phase change materials above is 3.4 times that of 30% phase change materials at the bottom.Taking the outer phase change curtain wall as the research object,combined with night ventilation,the passive regeneration of phase change wall is studied.The effects of phase change layer thickness,phase change point temperature,latent heat and ventilation period on thermal performance of wall and regeneration of phase change materials are analyzed.The results show that the optimal phase change temperature of phase change material is 29 ℃,the optimal latent heat is 150 k J / kg,the optimal thickness of phase change layer is 20 mm,the optimal period of night ventilation is21:00-09:00,and the utilization rate of phase change material is 29%,which is low.Taking the intervention period of refrigerant water and the intermittent duty cycle of capillary radiation air conditioning as the key parameters,combining the phase change layer with capillary radiation air conditioning,the active regeneration process of phase change materials is analyzed,and the optimization strategy of intermittent cooling regeneration is put forward.The simulation results show that through the intervention of active cooling capacity,the convection in the vertical direction of the phase change layer is more uniform,the liquid phase rate is 70%,16:00 p.m.is the best intervention time for regeneration,and 16:00-20:00 p.m.is the best intermittent working time of capillary radiation air conditioning.Compared with the ordinary phase change wall,the average indoor temperature is reduced by 5.19 ℃,the temperature fluctuation is reduced by 0.22 ℃,the regeneration time is 9h,the regeneration time is shortened by 3H,and the regeneration rate is increased by 0.3 times,The duty cycle of active cooling regeneration of phase change materials is 16.7%.