Trial Production Of Ternary Composite Phase Change Material Concrete

With the continuous development of industrial level and more and more prominent energy problems,people pay more and more attention to energy conservation and emission reduction.Among them,building energy consumption accounts for a large proportion in the total energy consumption,so how to achieve building energy saving is also an important issue at present.Phase change materials can absorb or release a part of latent heat from the environment in the process of material state change,so as to maintain the surrounding temperature is relatively stable in a certain time.By using the characteristics of phase change materials that absorb and store heat in melting state and release the stored heat in condensation,and combining phase change materials with common building materials,the indoor temperature can be adjusted,the thermal comfort of human body can be improved,and building energy saving can be realized.In this paper,cinnamate-palmitate-tetraol ternary composites were selected as phase change materials,and expanded perlite as carrier.Based on the method described in previous literature,the composite phase change materials of lauric acid-palmitate-tetraol / expanded perlite were prepared.The material was mixed into concrete in a certain proportion to prepare phase change concrete.Firstly,the composite phase change material will have leakage phenomenon in the process of phase change.in order to improve this problem,the composite phase change material is encapsulated by wet-wrapped cement powder.the mass loss rate test results show that the leakage of the encapsulated composite phase change material is obviously improved.In order to investigate whether cement hydration has a chemical effect on composite phase change materials during packaging,Fourier transform infrared spectroscopy was carried out.The results showed that the cement hydration process did not form a new chemical bond between the original materials.In order to explore the durability of phase change materials after packaging,the differential scanning calorimetry tests were carried out before and after phase change cycle,respectively.The results show that the latent heat of phase change is almost unchanged before and after phase change cycle.That is,the durability of phase change materials after packaging is good.Secondly,the preparation of concrete requires coarse aggregate and fine aggregate as well as cementitious materials.In this paper,ordinary medium sand and cement encapsulated composite phase change materials(hereinafter referred to as phase change aggregate)are used as fine aggregate,shale ceramsite as coarse aggregate,and ordinary concrete test blocks are made according to a certain proportion.Phase change concrete test blocks are prepared by replacing sand with 5%,10%,15% and 20% ratios of phase change aggregate.Through the test of compressive and tensile strength of concrete test block,the influence of aggregate content on the tensile and compressive properties of concrete is explored,and the influence of phase change cycle on the tensile,compressive strength and durability of phase change energy storage concrete is explored through phase change cycle test.The main conclusions are as follows :(1)under the same curing age,the compressive and tensile strength of phase change regenerative concrete decreases gradually with the increase of phase change aggregate content(2)after 20 phase change cycles,The compressive and tensile strength of phase change regenerative concrete have no obvious change.The phase change heat storage model room was built with 20% volume content of phase change concrete,and the ordinary concrete room was built as the control.By recording the changing trend of the inner and outer surface temperature of the regenerator during the process of rising and falling temperature,the absorbing and releasing curve is drawn,and the absorbing and releasing properties of the phase change regenerative concrete are analyzed.The results show that the time of phase change concrete house is obviously longer than that of ordinary concrete house,which indicates that the phase change concrete with 20% aggregate content can effectively play the function of phase change heat storage and exothermic.Finally,the thermal calculation results show that adding phase change aggregate to the wall can improve the thermal performance of the wall and reduce the thickness of the wall and save the material.