纳米多孔气凝胶玻璃系统气候响应特性的机理与实验研究

Glazing window and curtain wall are the weakest places for thermal insulation in buildings and have become a key factor for building energy efficiency. Nanoporous silica aerogel has excellent insulation adiabatic performance and good light transmittance. Aerogel glazing system can effectively improve the thermal insulation performance of windows. Due to rather complicated skeletal nanostructures, the transmission mechanism of solar radiation in aerogel is very complex. Right now, there has not been an accurate model to evaluate the response characteristics of aerogel glazing system to the changing climate conditions yet. This project intends to deduce the optimal parameters of aerogel in glazing system by inverse method through the energy balance principle for multi-layer transmittance system, to build the optical models for absorption and transmittance of solar radiation in aerogel by constructing the nanoporious random structures of aerogel and simulating the solar radiation intensity distribution in all angle directions under various incident angles with Monte Carlo ray-tracing method, to simulate the dynamic coupling process between solar absorption and internal heat conduction in aerogel glazing system by building the state space model of dynamic heat transfer with internal heat source, to experimentally validate the accuracy and correctness of the model and method for aerogel glazing system under actual weather conditions, to simulate and analyze the response characteristics of aerogel glazing system to diverse climate conditions, to optimize the construction and optimal parameters of aerogel glazing system, in order to provide the guidelines in theoretical methods and techniques for developing and reasonably utilizing energy-saving aerogel glazing system as well as reducing the energy consumption of glazing window and curtain wall.

玻璃外窗与幕墙是建筑最薄弱的保温隔热部位，是影响建筑节能的关键因素．纳米多孔气凝胶有优异的隔热性能和良好的透光性，气凝胶玻璃系统能有效改善窗户和幕墙的性能．由于气凝胶中复杂的纳米骨架结构，太阳辐射在气凝胶中的传播机理十分复杂，目前尚未有分析时刻变化气候条件下气凝胶玻璃气候响应特性的准确模型．本项目拟通过多层透过体系能量平衡原理反演推算气凝胶玻璃中气凝胶的光学参数；构建气凝胶的纳米多孔随机结构，用Monte Carlo射线跟踪法确定不同入射角下气凝胶中的光强分布规律，建立气凝胶对阳光吸收与透过的光学模型；建立有内热源的热传递状态空间模型模拟气凝胶玻璃吸收太阳辐射与内部热传导的动态耦合过程；在实际气候条件下实验验证气凝胶玻璃气候响应特性模型的正确性；模拟分析各种气候条件下气凝胶玻璃的响应特性，优化其隔热与光学性能，为开发和正确应用气凝胶节能玻璃，降低玻璃窗户与幕墙的能耗提供理论方法和技术指导．

气凝胶具有优异的隔热性能和良好的透光性，在中空玻璃中填充气凝胶能有效改善窗户和幕墙的性能。由于气凝胶中复杂的纳米骨架结构，目前尚未有气凝胶玻璃气候响应特性的准确模型，不利于气凝胶玻璃的开发和合理使用。本项目提出了确定气凝胶太阳辐射消光系数的实验和理论方法，探明了气凝胶玻璃随气候变化的响应机理，提出了气凝胶玻璃响应气候变化的机理模型和分析方法，分析了气凝胶玻璃在不同气候条件下的适用性。.在实际气候条件下搭建实验平台，测试气凝胶玻璃参数和室内外参数。用界面能量平衡方法建立气凝胶玻璃的太阳辐射透过模型，利用实验数据反推颗粒型气凝胶层的消光系数。用四参数随机生长模型构建板状气凝胶多孔结构，结合米散射和蒙特卡洛方法计算板状和颗粒型气凝胶的消光系数。用几何光学求解颗粒型气凝胶层的有效光学路径。建立了含有内热源的气凝胶玻璃动态热传递模型，模拟气凝胶玻璃随太阳辐射和室外气温变化的动态响应机理和特性，实验验证了模型的准确性。用该模型对气凝胶玻璃在我国各气候区的适用性进行了分析。结果表明，气凝胶玻璃在严寒和寒冷地区最适用，夏热冬冷地区次之。.本项目的顺利完成为开发和合理推广使用气凝胶玻璃提供了基础理论和方法支撑。