| The fatty acid phase change clean material has appropriate phase change temperature,high melting latent heat,no supercooling,non-toxic,non-corrosiveness,good chemical and thermal stability,and other advantages.However,single FA has high temperature,which limits its application field.In order to obtain PCM with moderate temperature and excellent performance,five kinds of FA are compounded to form FAM,it's application in the field of building energy conservation,which can effectively reduce indoor temperature fluctuation,improve the indoor environment of comfort,solve the problem of time and space mismatch between the energy supply and demand,expand its scope of application,reduce dependence on traditional petrochemical energy,alleviate the energy crisis,improve the ecological environment and provide a theoretical basis for its industrial production.Based on the five single FAs as raw materials and according to the lowest eutectic point theory,the components were blended and BFAM and TFAM were prepared by melt blending method to study the thermal properties and influencing factors.The results show that five BFAMs and three TFAMs had moderate temperature and good thermal performance.The phase change temperature can be improved by theoretically controlling the distribution ratio of the FAM group and met the requirements of the human body to the comfort temperature range of building(18?-28?).Using BFAM and TFAM as basic materials,and porous structure of FM and SG as carrier materials,CFAM-F and CFAM-S were prepared by melt impregnation method,and studied its thermal performance,heat release performance and cycle stability.The results show that the composite was physical blending with good compatibility and no leakage of the solid-liquid phase change.The phase transition temperature is basically unchanged before and after compounding.The mass loss rate of 500 times of the hot and cold cycle is within 8%,and the temperature damping ratio is between 242%and 935%.It indicates that the porous material of the mesh porous structure effectively protects the thermal properties and stability of the composite phase material and meets the application requirements of energy-saving buildings;The addition of high thermal conductivity EG to the composite phase can significantly improve its thermal conductivity which is increased by 2-15 times.Two small simulation rooms were designed and constructed to embed 15%LA-MA/TDFM and 12%LA-MA-PA/PDFM in the wall to simplify the room heat transfer model and select the winter climate conditions of Huainan from 2016 to 2018,and it's established relevant experimental verification and numerical calculation methods,using the solidification/melting transient analysis method to study the phase change heat transfer and self-tempering process.The results show that compared with common walls,the phase change simulation room has obvious self-temperature regulation effect,its insulation effect is 2 ??7 ?,the temperature damping rate is about 177%,and the energy saving efficiency is about 29%,the hottest or the coldest time of the day is smoothly transited,which obviously improves the heat storage capacity of the building wall,meeting the requirements of comfortable temperature for residential buildings,achieving the purpose of temperature control,energy saving and power saving.Numerical simulation of ANSYS software was used to study the effects of wall thickness and ambient temperature fluctuations on the change of room temperature.The results show that increasing wall thickness and ambient temperature can further improve the effect of temperature adjustment,and it's reasonably configured CFAM's phase change temperature,thermal properties,combination methods,and usage patterns,which can optimize CFAM's building energy efficiency. |
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