Research On Bionic Plants For Building Sunshade And Heat Prevention And Optimization

The most basic function of the building is to provide shelter for people from wind and rain.More than half of the population live in the hot climate area of our country.In these areas,more and more houses must be designed to prevent heat.Plants have unique physiological structure and characteristics,can adapt to changing weather conditions,and have a natural ability to adapt to climate.At the same time,plants have been used to improve the building environment.A typical natural inspired way of heat protection is vertical greening or roof greening.However,there are some problems in the development of three-dimensional greening,such as high maintenance cost,big influence of season and region on plant growth,easy to grow mosquitoes and so on.Based on the analysis of the cooling mechanism of the plant itself and the building,this paper proposes to use the plant cooling mechanism for biomimetic,so as to achieve the effect of building heat prevention,so as to retain the advantages of the plant in building heat prevention and solve its shortcomings.In this paper,the real and false blade shading is selected as the research object,and the main work is as follows:First of all,based on the shading effect of bionic leaves corresponding to or similar to real leaves,four types of real leaf materials and bionic leaf materials were selected-polyester for ivy,clay resin for stone lotus,aluminum resin for silver leaf,and PE for wintergreen,Compare and test their short wave reflectance and long wave emissivity,and analyze the suitability of the shading of the blade material based on the ratio of reflectance to emissivity.The results showed that the silver leaf chrysanthemum had the best adaptability to shading in real plant leaves,and the aluminum sheet had the best shading adaptability in bionic leaf materials.Secondly,in order to better understand the temperature drop and canopy shading effect of real and fake leaves under the same climatic conditions,this chapter selects suitable real plant leaves as samples to make bionic leaves and their single canopy on the basis of the same chapter.Under climate conditions,the temperature drop effect of a single true and fake leaf was compared and tested,and the effects of differentmaterials and different coverages of the single-layer canopy leaf of Ivy on its shading effect were investigated.Based on the temperature drop of a single true and fake leaf and the weather resistance and plant morphology of the material,Ivy was selected as the canopy plant sample,and polyester and aluminum sheets were used as the corresponding bionic materials.Through different materials-real ivy,polyester,and aluminum sheets Comparison of the three canopy shading experiments.The experimental results show that the aluminum sheet has the best shading effect.By using different coverage rates-55.7%,76.3%,89.4%-comparison of canopy shading experiments of polyester materials,the experimental results show that the coverage rate is The shading effect is the best at 89.4%,but the difference from the coverage rate of 76.3% is small.From a comprehensive perspective,the shading device with the coverage rate of 76.3% is the most suitable.Thirdly,after the canopy shading effect of real and fake leaves was measured,the physiological role of plants,transpiration,played an important role in the study of plant cooling mechanisms.Based on Chapter 3,this chapter selects the ivy single-layer canopy as the research object,measures the leaf evaporation,and uses a combination of solid model and mathematical model to establish simplified energy calculation equations for sunshade,evaporation and convection.The heat transfer process was quantified and the evaporation of the single-layer leaf of the ivy canopy was predicted.The results show that,based on the calculation of the energy formula,the radiation and convection of the single-layered ivy leaf are the active methods of heat dissipation;in the actual measurement and prediction of the evaporation,the trend and the measured result are similar.Finally,based on the application of transpiration to the cooling mechanism of plants and bionics,the principle of water absorption by the roots of the plant-capillary action,was selected to absorb water-resistant and weather-resistant materials-coolpus fibers and the bionic materials selected earlier-polyester and aluminum sheets Compounding was performed to improve water absorption and verify the effect of temperature drop.The results show that the water-improved leaves have a significant cooling effect compared with the raw material leaves.