Preparation Of The Shape-stabilized PCMs And Experiemtal Study In The Thermal Characteristic Of PCM Room Model

Latent heat storage is one of the most efficient ways of storing thermal energy. Unlike the sensible heat storage method, the latent heat storage method provides much higher storage density, with a smaller temperature difference between storing and releasing heat. Energy storage in the walls, ceiling and floor of buildings may be enhanced by encapsulating suitable phase change materials (PCMs) within these surfaces to capture solar energy directly and increase human comfort by decreasing the frequency of internal air temperature swings and maintaining the temperature closer to the desired temperature for a longer period of time. PCMs have been the most potential and wide applied materials and the focus of research on energy saving and material scientific.We use buytle stearate as PCM,several kinds of porous materials as supporting materials and prepare for shape-stabilized PCMs.Stablish PCM model and analyze the effect of adjusting temperature.The PCM we used in this study has phase change temperature 20℃,latent heat140J/g.It's phase change temperature meets the requirement of people's comfort degree.There are plaster board,expanded perlite,expanded vermiculite and montmorillonite as supporting materials.Physical adsorption method was used to prepare shape-stabilized PCMs. To determine the preparation technology of preparing PCM board and mortar,thermal behavior and other performance were analized.The PCM board has absorption rate 60%,latent heat 51.8418J/g.EP-BS PCM grain has absorption rate 180%,latent 92.2015J/g respectively.PCM mortar was prepared from mixing PCM grain with cement and water.Expanded graphite was also incorporated for improving thermal conductivity of PCM mortar.Thermal conductivity increased 71.6% when content of EG was 10%.Construction mix proportion was given as PCM grain:cement:water:EG=1:1.25:1.88:0.1.PCM model was established for analyzing the energy saving effect when PCM incorporated.Construction technology was also determined.Standard temperature damping rate was introduced which was 26.7% in this study.Another model was established for analying the actual adjusting temperature effect of PCM.The experiment result shows as follows:when phase change happening in a cycling period,the maximum tempreture at daytime of PCM room model was 2~3℃lower than that of ordinary room,minimum temperature at night was 1~2℃higher,and presented time was retarded 1.5~2h.In this condition,the heat flux of eastern wall changes differently.If there was no phase changing in a cycling period,PCM also showed the ability of adjusting temperature effect because the whole heat capacity of the PCM wall was improved.