Research On The Preparation And Performance Of High Temperature Phase Change Heat Storage Materials From Construction Waste

With the rapid development of society,more and more attention has been paid to environmental and energy utilization problems.Improper disposal of construction wastes not only pollutes the environment,but also wastes resources.In order to make use of these construction wastes and increase their functionality,the waste ceramics and glass from construction wastes were the main raw materials to prepare recycled bricks,and added a certain amount of phase change materials and sintering aids to prepare composite materials with thermal storage properties.Based on the waste ceramic and glass in the construction wastes as main raw materials,added suitable amount of additives,under the condition of the sintering temperature was 930?1180? and the holding time was 60?160min,the recycled bricks of a certain strength were successfully achieved.The different NaCl content of composite phase change heat storage materials were made by joining NaCl on the basis of a proportional,in,under the condition of the sintering temperature was 850?1050? and the holding time was 40?120min.The effects of raw material ratio and sintering process on physical and mechanical properties of recycled bricks and composite phase change heat storage materials were analyzed.The phase composition and microstructure of recycled bricks and NaCl/recycled brick composite phase change thermal storage materials were analyzed by XRD and SEM.Heat storage performance of heat storage materials was characterized by TG-DSC test and thermal cycle tests?The results show that when the waste ceramic content is 55%and the waste glass content is 28%,the water absorption rate of recycled brickl is 0.04%,the volume density is 2.39g/cm3,and the bending strength is 48.53mpa.Through the analysis of phase composition and microstructure,it can be seen that the main reason of the strength of recycled brick was the formation of mullite,and with the increase of the waste glass content,the porosity of recycled brick became lower and lower,and the strength became higher and higher.Based on the phase composition and microstructure analysis of NaCl/recycled brick composite phase change heat storage material,it can be seen that NaCl and recycled brick were well combined,and mullite was formed in inorganic salt medium at low temperature.An obvious heat absorption peak was observed when the temperature was about 800 ? by the DSC curve.NaCl/recycled brick composite phase change heat storage material has the best performance when NaCl content is 40%.The latent heat was 59.72J/g,the heat storage density was 221.746J/g,and the thermal conductivity was 0.72W/(m·K).After several thermal cycle tests,the weight loss rate of the heat storage materials were small,and the phase of the materiasl were unchanged basically,indicating that the heat storage materials had good thermal stability.