A coupled heat and formaldehyde migration model based on the non-equilibrium thermodynamic theory and molecule movement theory was developed.The effect of temperature on the transport coefficients was simulated,and th...A coupled heat and formaldehyde migration model based on the non-equilibrium thermodynamic theory and molecule movement theory was developed.The effect of temperature on the transport coefficients was simulated,and the simulation results were validated with experimental data from the literatures.The calculation shows that air exchange rate larger than 2 h-1 should be prevented,if the purpose is only for formaldehyde emissions control.The effects of temperature on formaldehyde migration are obvious.展开更多
The heat transfer performance of the phase change materials used in free cooling and air conditioning applications is low,due to the poor thermal conductivity of the materials.The recent phenomenal advancement in nano...The heat transfer performance of the phase change materials used in free cooling and air conditioning applications is low,due to the poor thermal conductivity of the materials.The recent phenomenal advancement in nano technology provides an opportunity for an appreciable enhancement in the thermal conductivity of the phase change materials.In order to explore the possibilities of using nano technology for various applications,a detailed parametric study is carried out,to analyse the heat transfer enhancement potential with the thermal conductivity of the conventional phase change materials and nano enhanced phase change materials under various flow conditions of the heat transfer fluid.Initially,the theoretical equation,used to determine the time for outward cylindrical solidification of the phase change material,is validated with the experimental results.It is inferred from the parametric studies,that for paraffinic phase change materials with air as the heat transfer fluid,the first step should be to increase the heat transfer coefficient to the maximum extent,before making any attempt to increase the thermal conductivity of the phase change materials,with the addition of nano particles.When water is used as the phase change material,the addition of nano particles is recommended to achieve better heat transfer,when a liquid is used as the heat transfer fluid.展开更多
城市存量居住建筑量大面广,建设年代差异大,工程量清单缺失严重,基于碳排放清单探究城市建筑物化阶段碳排放量空间差异难度大。因此,研究在单体建筑碳排放基础上,分析了建筑物化阶段碳排放量影响因素,并建立了城市居住建筑物化阶段碳排...城市存量居住建筑量大面广,建设年代差异大,工程量清单缺失严重,基于碳排放清单探究城市建筑物化阶段碳排放量空间差异难度大。因此,研究在单体建筑碳排放基础上,分析了建筑物化阶段碳排放量影响因素,并建立了城市居住建筑物化阶段碳排放量预测模型。结果显示:建筑高度、建筑总面积与建筑物化阶段碳排放量存在近似线性关系,决定系数(R^(2))分别为0.57、0.83;综合建筑高度与建筑总面积建立的建筑物化阶段碳排放量预测模型拟合效果较好,平均决定系数(R^(2))为0.86,平均绝对误差百分比(Mean Percentage Error,MAPE)为16.19%。根据碳排放量预测模型,结合地理信息系统(Geographic Information System,GIS)空间分析,获得了居住建筑物化阶段碳排放量空间分布,结果表明:以西安市为例,居住建筑物化阶段碳排放总量空间分布呈现“南多北少、西密东疏”的特点;单位面积碳排放量差异较小,呈现由边缘城区向中心区域逐渐递减的分布特点。研究建立了一种可广泛应用于城市尺度的居住建筑物化阶段碳排放量预测模型,为构建低碳化城市建筑空间发展格局提供了数据支撑和方法指导。展开更多
文摘A coupled heat and formaldehyde migration model based on the non-equilibrium thermodynamic theory and molecule movement theory was developed.The effect of temperature on the transport coefficients was simulated,and the simulation results were validated with experimental data from the literatures.The calculation shows that air exchange rate larger than 2 h-1 should be prevented,if the purpose is only for formaldehyde emissions control.The effects of temperature on formaldehyde migration are obvious.
文摘The heat transfer performance of the phase change materials used in free cooling and air conditioning applications is low,due to the poor thermal conductivity of the materials.The recent phenomenal advancement in nano technology provides an opportunity for an appreciable enhancement in the thermal conductivity of the phase change materials.In order to explore the possibilities of using nano technology for various applications,a detailed parametric study is carried out,to analyse the heat transfer enhancement potential with the thermal conductivity of the conventional phase change materials and nano enhanced phase change materials under various flow conditions of the heat transfer fluid.Initially,the theoretical equation,used to determine the time for outward cylindrical solidification of the phase change material,is validated with the experimental results.It is inferred from the parametric studies,that for paraffinic phase change materials with air as the heat transfer fluid,the first step should be to increase the heat transfer coefficient to the maximum extent,before making any attempt to increase the thermal conductivity of the phase change materials,with the addition of nano particles.When water is used as the phase change material,the addition of nano particles is recommended to achieve better heat transfer,when a liquid is used as the heat transfer fluid.
文摘城市存量居住建筑量大面广,建设年代差异大,工程量清单缺失严重,基于碳排放清单探究城市建筑物化阶段碳排放量空间差异难度大。因此,研究在单体建筑碳排放基础上,分析了建筑物化阶段碳排放量影响因素,并建立了城市居住建筑物化阶段碳排放量预测模型。结果显示:建筑高度、建筑总面积与建筑物化阶段碳排放量存在近似线性关系,决定系数(R^(2))分别为0.57、0.83;综合建筑高度与建筑总面积建立的建筑物化阶段碳排放量预测模型拟合效果较好,平均决定系数(R^(2))为0.86,平均绝对误差百分比(Mean Percentage Error,MAPE)为16.19%。根据碳排放量预测模型,结合地理信息系统(Geographic Information System,GIS)空间分析,获得了居住建筑物化阶段碳排放量空间分布,结果表明:以西安市为例,居住建筑物化阶段碳排放总量空间分布呈现“南多北少、西密东疏”的特点;单位面积碳排放量差异较小,呈现由边缘城区向中心区域逐渐递减的分布特点。研究建立了一种可广泛应用于城市尺度的居住建筑物化阶段碳排放量预测模型,为构建低碳化城市建筑空间发展格局提供了数据支撑和方法指导。
