Application Development And Performance Of Cement-based Photothermal Conversion Materials

With the rapid development of society and the dramatic consumption of energy.Energy crisis and environmental problems have become the two major problems facing today’s society.Solar energy as an efficient,clean and sustainable energy,if it can be absorbed and applied to building materials,which can well alleviate the energy crisis and solve the environmental problems such as urban flooding,water pollution and water shortage brought about by the rapid development of society.In this project,a functional concrete with photothermal conversion and thermal storage was prepared by combining cement as the base material with photothermal materials and thermal storage materials.It can be applied to building structures to provide a new idea for energy saving and environmental protection.The specific work in this project is as follows:（1）In this paper,porous cement photothermal conversion materials（PCPCM）were prepared by using cement as the base material,aluminum powder as the initiator and carbon material as the photothermal coating.Then,the pore structure,hydrophilicity,water absorption,light absorption performance,photothermal conversion performance,and rainwater purification performance of PCPCM were studied.The experimental results shown that the porous cement-based photothermal conversion material has a good structure of pores and shows super hydrophilic and excellent water absorption under the capillary action,which can quickly absorb and store water.Due to the carbon material was loaded on the surface of porous cement-based,the PCPCM exhibited excellent light absorption performance in the wavelength range of 3000nm to 2500nm（>90%）.The PCPCM exhibited good water evaporation efficiency and photothermal conversion efficiency under one sunlight intensity(1.0 KW m^-2).In which the water evaporation efficiency of graphene-cement-based photothermal conversion materials could reach 1.16 kg m2 h-1 and the photothermal conversion efficiency was 76%.In addition,the PCPCM also exhibited excellent water purification function,which can evaporate and purify the water stored inside it.The PCPCM can be used in pavements structures,which can well achieve the absorption,storage and purification of rainwater after rain.It provides a new idea to solve the water shortage and the construction of functional sponge city.（2）In this paper,photothermal conversion energy storage concrete（PHSC）was prepared with cement as the base material,super absorbent polymer（SAP）as the heat storage medium,carbon black as the photothermal material and graphite as the heat conductivity medium.Then,the photothermal conversion performance,heat storage performance,volumetric stability performance of PHSC were investigated.The experimental results shown that the PHSC could quickly absorb,convert and store sunlight,and has excellent photothermal conversion performance and thermal storage performance.Compared with ordinary concrete,the PHSC could absorb more heat,1.48 times more than ordinary concrete,which can be used in building materials to reduce building operation energy consumption and regulate indoor and outdoor temperature.In addition,the SAP was added to concrete could greatly increase the relative humidity inside the concrete,providing sufficient moisture for the early curing of concrete and significantly reducing the shrinkage phenomenon of concrete,and after 8.4%SAP was added in concrete,curing 21 days,drying shrinkage is only 0.02%.