Research On New Environmental Matrix Based On Green Roof Energy Saving

Green roof can reduce the roof surface temperature,reduce building energy consumption,improve the urban environment,as an ecological energy-saving measures have been widely recognized.However,due to the high bulk density of roof greening soil,the thickness is usually 15cm or more,resulting in an increase of building load,affecting the building structure,combined with a large number of green roofs require a lot of green roof irrigation and conservation costs,greatly limiting the popularity of green roofs.In view of the shortcomings of the existing technology,this paper prepares biochar from branches and straw of agricultural wastes and mixes it with municipal solid waste sludge and soil to develop a simple and easy-to-use raw material with low cost and small dead weight,Rich in nutrition and moisture,with good water retention and fertility performance green roof cultivation matrix,study its environmental effects and the effect of indoor cooling,and its energy consumption and economic analysis,with a view to solve the existing green roof High soil bulk density and greening costs,high maintenance costs and other issues,but also to solve the urban solid waste sludge and agricultural waste branches,straw and other resource utilization problems.The main research results are as follows:1.Rice straw and citrus fruit biochar had better adsorption effect on Pb²⁺.Considering the pH value of soil,the capability of adsorbing heavy metals and the water and fertilizer holding capacity of biochar,citrus fruiting branch biochar with mass percentage of 1%to 5%As a green roof cultivation substrate component.2.Based on the purpose of the normal growth of light plant and green plant in planting layer,it was determined that the ratio of sludge to soil in planting layer was 1:1,the thickness of planting layer was 6cm and the planting density was 6.4cm²/plant.3.The optimization scheme of the new light green roof cultivation substrate by response surface methodology is as follows:the sludge moisture content is 80%,the sludge content is 50%,the biochar content is 5%and the soil content is 45%.4.The new lightweight green roof shows good thermal insulation after continuous temperature observation in summer hot weather.During the test period,the matrix with optimized matrix ratio had a lower indoor average temperature of 10℃than that of the pure sludge matrix and a 20%decrease of temperature fluctuation.The new light green roof could achieve higher thermal comfort and thermal satisfaction Through the software simulation analysis,if the new lightweight roof greening of the 660m² flat roof in Chongqing can be saved,it can save 7547kW·h/year.Under the government subsidy,the dynamic payback period is 10 years.