Research And Mechanism Analysis Of Thermal Insulation Performance Of Environmentally Friendly Coatings

The sun,as the main source of earth's energy,provides tremendous energy to people's life and productive activities.However,in hot climates,excessive solar radiation causes buildings to rise in temperature,and increased demand for air conditioning for cooling leads to high energy consumption.In order to mitigate global warming and the greenhouse effect,thermal insulation of buildings is considered as one of the most cost-effective measures.The traditional thermal insulation materials need to be applied thickly,occupying the available space of buildings,absorbing water and cracking easily.Therefore,it is necessary to develop and research new and efficient building thermal insulation coatings.In response to this situation,this paper presents a new water-based environmentally friendly insulation coating.Thermal insulation coating was prepared with different ingredients,water-based acrylic emulsion as a filmforming material,rutile titanium dioxide and sericite powder as a pigment,five different sizes of hollow glass microspheres and silica aerogel as a thermal insulation filler.The effects of addition amount of hollow glass microspheres,particle sizes,compound of different hollow glass bead,and coating thickness on the insulation performance of the coating were investigated through a self-made insulation test device.The results show that when the thickness of the coating is 0.25 mm and the hollow glass microspheres is added with a single particle size,the coating layer of the hollow glass microspheres with the median particle size of 27.85?m added with 10% mass fraction has the best thermal insulation performance,16.1 ? lower than blank tinplate;The coating layer of five kinds of hollow glass microspheres mixed with 1: 1: 1: 1: 1 with a mass fraction of 10% have the best thermal insulation properties,17.1 ? lower than the blank tin plate.When the thickness of the coating layer is 1.75 mm,the coating layer of the hollow glass microspheres with the median diameter of 27.85?m added with a mass fraction of 10% has the best thermal insulation performance,17.9 ? lower than the blank tin plate.The prepared thermal insulation coating has good elasticity which offers better ability to bond with the substrate to avoid cracks.It also has a high solar reflectance,lower thermal conductivity,used in buildings can effectively reduce solar radiation under the outer wall of the building,to achieve significant energy savings.Then the heat transfer process of the coating was simulated by ANSYS finite element software,and the simulated value of the thermal conductivity of the coating was calculated according to the result.The simulation results show that the thermal conductivity of the thermal insulation coating decreases with the increase of the volume fraction of the thermal insulation filler,compared with the measured results,the simulation results of the thermal conductivity of the thermal insulation coating filled with hollow glass microspheres and aerogel decreases linely as the fill volume fraction of the thermal insulation filler increases.Compared with the measured value,when the hollow glass microspheres were filled,the simulation results with the content of 2wt% were 5.9% larger than the measured value.