Study On Reflective Properties And Application Of Thermochromic Materials

The urban heat island effect and building energy consumption are issues that the scientific community continues to pay attention to.Due to the rapid expansion of the urban population,the dense building layout has seriously affected the urban microenvironment.The control of the local temperature increase of the building has a positive effect on the urban heat island effect.In terms of the reflectivity of the envelope structure in response to solar radiation,the increase or decrease of its value affects the temperature of the envelope structure of the building.Related studies have shown that from the perspective of energy consumption,when the temperature decreases by 2-3 degrees Celsius,the energy consumption of air conditioning Significantly reduced,can effectively save 10%-15% of the city’s summer electricity,and effectively reduce carbon dioxide emissions,alleviate the urban heat island effect from the application.Therefore,the research on the reflection characteristics of the building envelope structure material should have a positive significance to its actual.Building materials play an important role in the thermal environment of urban space,building energy consumption and indoor environmental quality.Thermochromic material,which can use in the building envelopes,with its special optical properties of its reflectance that change by temperature.the materials appearance of color is difference and its reflect and absorb solar radiation differently.when the temperature is increased,the appearence of color is light,and the reflectance is increased;when the temperature is decreased,the appearence of color is dark,the absorption rate is increased.the dynamically changing reflectance makes it have potential for energy-saving.This thesis focuses on reversible thermochromic material of buildings,analyzes the factors that affect its reflectance characteristics and the fact that the changes of the material’s own properties affect the environment.By the experimental design,we can use in the aualitative and quantitative analysis of thermochromic materials.The spectral reflection characteristic curves of the material under different temperature conditions,different material components,and different incident angles are extracted by a spectrometer.Based on spectral analysis and chromaticity theory,on the basis of the ratio of existing material,through the control of the material composition,the corresponding spectral reflectance characteristic curve is analyzed and extracted,we discussed the optimized ratio of material application.In the visible light range,complete the color calibration by sampling the spectral reflection characteristic curve,record the chromaticity and lightness of the color sample,which can help us to promote the replacement of ordinary paint by color-changing materials;Based on the optical properties of the material,the reflectance of the thermochromic materials with different temperature change points is calculated,combined with different building climate zones and simulating the output of cooling and heating loads,in order to find out the potential of energy saving of the thermochromic materials.In short,the research on the reflectance characteristics of materials can help the materials adapt to the environment during the application process and bring beneficial effects to the local environment through their own optical properties.The conclusion based on the experimental research is as follows:First,in the analysis and research of the reflectance characteristic curve,the thermochromic material is within the temperature change threshold range,which causes the change in the reflectance of the thermochromic material due to the different pigment or filler ratio of the combined material and the angle of light incidence.In the range of visible light,the change of color samples with temperature changes increases the surface brightness of the material significantly,while the reflection characteristics of different color samples in the state of high temperature are similar.Second,in the actual application stage,the thermochromic material has a high adaptability to the climate including of different seasons and the weather transition period.The dynamic optical behavior of thermochromic material has a positive significance for reducing energy consumption in buildings.For different climate zones in China,the same type of thermochromic materials have different capabilities to reduce heating and cooling loads.In terms of material selection,the design of temperature change points and the range of reflectance thresholds should be used to achieve high adaptability to the climate environment.Building materials play a vital role in the thermal environment of urban spaces,as well as in building energy consumption and indoor environmental quality.The development of adaptive materials suitable for the built environment is widely respected,and temperature-sensitive color-changing architectural coatings can be used as building envelope materials with optical properties.Their reflectance changes with temperature and presents different colors.At high temperatures,its apparent color appears light and its reflectance increases;at low temperatures,its apparent color appears dark and its absorption rate increases.It is an effective experimental material for studying the relationship between appearance color and building energy efficiency.This thesis focuses on the reversible building thermochromic materials.By measuring the factors that affect its reflection characteristics and the fact that the material’s own property changes affect the environment,the experimental design is carried out,and the thermochromic materials are qualitatively and quantitatively analyzed.In the visible light range,the spectral reflection characteristic curves of materials under different temperature conditions,different material components,and different incident angles are extracted by a spectrometer.Calculate the reflectivity of thermochromic materials with different temperature change points based on the optical properties of the materials,and combine them with the climatic zone of the building to tap the energy-saving potential of thermochromic materials.Based on spectral analysis and chromaticity theory,Based on the material ratio of the material,by controlling the composition of the variable material and extracting the corresponding spectral reflectance characteristic curve,the optimal ratio of the material application is discussed;in the visible light range,the color calibration of one of the factors affecting the spectral reflection characteristics is adopted.Record the chromaticity and lightness of the color samples,and promote the replacement of ordinary coatings by materials;the research on the reflectivity characteristics of materials helps the materials to adapt to the environment in the application process and bring beneficial effects to the local environment through their own optical properties.The conclusions based on experimental research are as follows:First,in the analysis and research of the reflectivity characteristic curve,the temperature-sensitive color-changing material is within the range of the temperature change threshold,and the reason for the change in the reflectance of the temperature-sensitive color-changing material is the angle of light incidence of the pigment and filler of the combined material.In the visible light range,the change of color samples with temperature changes significantly increases the brightness of the material surface,and the reflection characteristics of different color samples in the light color state are similar.Secondly,in the simulation experiment of energy consumption,the thermochromic materials are highly adaptable to the climate in the actual application stage,with different seasonal changes including the weather transition period.Through dynamic optical behavior,it has positive significance for reducing energy consumption in buildings.