Thermal Properties Of Phase Change Energy Storage Material For Building Energy Conservation

With the rapid development of society, energy conservation has been widespread concernaround the world. Energy storage technology, by storing or releasing the latent heat fromsolid-liquid phase changing of phase change materials, has broad application prospectsin many fields. Phase change materials can store and release energy during phasechange process, so applying phase change materials to the constructions can reduce theroom temperature fluctuations, realize the room temperature adjustment, and improvethe room comfort and energy utilization. The thermal conductivity and phase transitiontemperature are important parameter of phase change materials, but the thermalconductivity affects the application of phase change materials. Coefficient of thermalconductivity of phase change energy storage device is directly related to the size of theenergy storage and the coefficient of release, the defect of phase change materials is itslower thermal conductivity. Measuring and enhancing the heat conductivity of phasechange materials have become a necessary work in this material development. Phasechange energy storage mortar board used in the construction of the building envelopewas made of phase change material and cement mortar， then studying thethermo-physical properties of Phase change energy storage mortar.In this paper, decanoic acid/hexadecanol and fly ash are used as the phase changematerials, the thermal conductivity of decanoic acid-hexadecanol composite phasechange materials and fly ash composite phase change materials were determined bythermal probe method and data filtering method. Test results indicate that theconduction coefficient of phase change materials in solid phase before the starting of thephase change and in liquid phase after the end of the phase change is relatively stable,and the coefficient of thermal conductivity in solid phase is slightly higher than itsliquid phase.By adding different mass fraction of expanded graphite in the fly ash compositephase change energy storage material to improve the performance of the heat transferconditions, and the test results indicate that adding10%of graphite on the fly ash toimprove the coefficient of thermal conductivity of composite phase change energystorage material is most obvious, has a good economy.Contrast test was operated by comparing cement mortar with phase change energystorage mortar board, under the same heating and cooling time, it is found that the warming and cooling rate of the phase change board were lower than the normal one,there was a large temperature and time differences between them, the biggesttemperature and time difference can be reached to20℃a nd42min,separately.By adding fly ash phase change material containing10%graphite composite intothe cement mortar to make the phase change energy storage mortar，and study the thethermo-physical properties of mortar preparation phase change energy storage. Theresults showed that the phase change energy storage mortar applied to the buildingenvelope have such features： excellent thermostat performance； smaller volumedensity； better alleviate their load-bearing construction；larger heat storage density；smaller leaks；stable performance；better durability.