摘 要

党的十九大指出，要坚持推进绿色发展，推进资源全面节约和循环利用。

而随着建筑能耗比例持续增高，屋顶绿化作为节能设计的重点技术之一，拥有巨大的节能潜力。绿化屋顶对改善建筑室内热环境、降低能耗指标有重要作用，对增加城市绿地面积、改善日趋恶化的城市生态环境也具有重要意义^[1]。但是绿化屋顶的应用具有一定的地域性特点，因此，在特定地区的气候条件下对绿化屋顶的热工性能进行研究不仅具有重要的理论意义，同时也具有十分重要的工程应用价值^[2]。

基于以上背景，本文首先通过文献调研对屋顶绿化的发展和研究方向进行了深入了解，在此基础上确立了以绿化屋顶热工性能和能耗水平为研究对象，以建筑屋顶内外表面温度、室内空气平均温度、建筑全年能耗等为研究指标的建筑能耗仿真模拟方案。并对能耗模拟软件 EnergyPlus中采用的植被屋顶模块的数学模型进行了学习，了解了EnergyPlus描述植被屋顶的各种参数及其含义。然后基于武汉地区的气候特点和相应的建筑热工以及建筑节能要求，借助建模软件SketchUp，建立了一个三层小型办公楼的建筑模型，并对该模型的各类属性进行设置，最后采用OpenStudio软件对该屋顶绿化建筑进行仿真模拟，定量研究了武汉地区屋顶绿化建筑的节能效果，并对绿化屋顶热工性能参数敏感性以及关键参数对能耗的影响进行了分析。

模拟结果显示，在夏季，绿化屋顶能有效降低屋顶外表面温度、屋顶内表面温度和室内平均空气温度，平均温度降幅分别为27.07℃、0.66℃和0.27℃。与非绿化屋顶相比，绿化屋顶能显著降低屋顶外表面温度波幅和屋顶内外表面温差，可使屋顶外表面的最大温度波幅从51.07℃降至24.45℃（降低51.92%），平均温度波幅从45.84℃降至16.90℃（降低63.13%）；绿化屋顶各项参数中，叶面积指数LAI和土壤层厚度对绿化屋顶的隔热性能影响最大；当绿化屋顶的土壤层厚度为0.15m、LAI为5时，建筑的总能耗指标最低，为14.80 kW·h/m²；当绿化屋顶的土壤层厚度为0.1m、LAI为5时，建筑的供冷能耗指标最低，为10.98 kW·h/m²；当绿化屋顶的土壤层厚度为0.2m、LAI为0.1时，建筑的采暖能耗指标最低，为3.69 kW·h/m²。

模拟数据证实了绿化屋顶在武汉地区具有较好的节能效果，并得到了武汉地区绿化屋顶的关键参数（叶面积指数、土壤层厚度）及其最佳取值范围。能耗数据显示绿化屋顶可显著降低武汉地区同类建筑的能耗水平，具有较好的环境和节能效益。

关键词：武汉地区；屋顶绿化；数值模拟

Abstract

The 19th Party Congress pointed out that we must continue to promote green development and promote comprehensive resource conservation and recycling. As the proportion of energy consumption in buildings continues to increase, roof greening, which has enormous potential for energy conservation, has become one of the key technologies for energy-saving design. Green roof plays an important role in improving the indoor thermal environment and reducing energy consumption of buildings, and it can also help increase urban green space and improve the deteriorating urban ecological environment. However, the application of green roofs has certain regional characteristics. Therefore, studying on the thermal performance of green roofs under the climate conditions in specific areas not only has an important theoretical significance, but also has very important engineering application values.

Based on the above background, the author first conducted a literature research on green roofs so as to have a comprehensive understanding of the development and its research frontiers. Then the author chose the thermal performance and energy consumption level of roof greening buildings as the study object and formulated a detailed research plan using the Surface Inside/Outside Face Temperature of Green Roof, Zone Mean Air Temperature and Zone Energy Consumption as the research indicators. Next, the author studied the mathematical model of the Roof Vegetation module implemented in EnergyPlus and figured out the exact meaning of all the parameters used to describe the Roof Vegetation module. At last, based on the climate characteristics of Wuhan and the corresponding requirements on building thermal properties and building energy saving performance, the author used SketchUp to build a three-story small office building model and conducted a quantified simulation analysis. The energy-saving effect of green roof construction in Wuhan area was analyzed, as well as the sensitivity of parameters of green roof thermal performance and the impact of key parameters on energy consumption.

The simulation results show that in the summer, the green roof can effectively reduce the Surface Inside Face Temperature of Green Roof, Surface Outside Face Temperature of Green Roof and Zone Mean Air Temperature, the average temperature drop was 27.07 °C, 0.66 °C and 0.27 °C, respectively. Compared with non-green roofs, green roofs can significantly reduce the temperature fluctuations on the outer surface of the roof and the temperature difference between the inner and outer surfaces of the roof. The maximum temperature fluctuation on the outer surface of the roof can be reduced from 51.07°C to 24.45°C (with a reduction of 51.92%). The average temperature fluctuation is from 45.84. °C dropped to 16.90 °C (reduced by 63.13%); among greening roof parameters, LAI and Thickness had the greatest influence on the thermal insulation performance of green roofs; when green roofs had a soil layer thickness of 0.15m and LAI was 5, the building’s total energy consumption was the lowest at 14.80 kW·h/m²; when the soil layer thickness of the green roof was 0.1m and the LAI was 5, the building’s cooling energy consumption was the lowest at 10.98 kW·h/m²; when the soil layer thickness of the green roof is 0.2m and the LAI is 0.1, the heating energy consumption is the lowest at 3.69 kW·h/m².

The simulation results confirm that the green roof has a good energy-saving effect in the Wuhan area. And the key parameters (Leaf Area Index and Thickness) of green roofs in Wuhan area and its optimal range were obtained. The energy simulation result shows that the green roof can significantly reduce the energy consumption level of similar buildings in the Wuhan area, and has better environment and energy-saving benefits.