Properties of construction materials [32].

In response to the issues of low land utilization efficiency and poor nighttime thermal performance in old single-slope solar greenhouses (SSG) commonly found in northern China, this study proposes renovation measures that expand the cultivation area and interior space by adding a shaded room and lowering its ground level. These modifications transform the original SSG into a double-slope solar greenhouse (DSG) and a sunken double-slope solar greenhouse (SDSG). Computational Fluid Dynamics (CFD) was employed to simulate and analyze the thermal environments of the three greenhouse types. The results indicate that, in winter, the peak temperature of the sunlit side in the SDSG is 1.9°C higher than that in the SSG; the temperature of the shaded side in the SDSG is 0.88–1.81°C higher than that in the DSG; compared with the rear wall of the SSG, the heat flux density of the middle wall in the SDSG is 10.19 W/m² lower, and is similar to that of the DSG middle wall, but the duration of heat release is longer in the SDSG; in comparison to the SSG and DSG, the annual thermal stability index of the SDSG is improved by 70% and 8.5%, respectively.

针对中国北方地区普遍存在的老旧单坡面太阳能温室（single-slope solar greenhouse, SSG）土地利用率偏低、夜间热性能欠佳的问题，本研究提出通过增设阴室并降低地面标高以拓展种植面积与内部空间的改造方案。该改造可将原有单坡面太阳能温室分别改造为双坡面太阳能温室（double-slope solar greenhouse, DSG）与下沉式双坡面太阳能温室（sunken double-slope solar greenhouse, SDSG）。本研究采用计算流体动力学（Computational Fluid Dynamics, CFD）对三类温室的热环境开展模拟与分析。研究结果显示：冬季时，下沉式双坡面太阳能温室采光侧的峰值温度较单坡面太阳能温室高出1.9℃；其背阴侧温度较双坡面太阳能温室高出0.88~1.81℃；相较于单坡面太阳能温室的后墙，下沉式双坡面太阳能温室中墙的热流密度低10.19 W/m²，且与双坡面太阳能温室中墙的热流密度相近，但下沉式双坡面太阳能温室的放热持续时长更长；与单坡面太阳能温室、双坡面太阳能温室相比，下沉式双坡面太阳能温室的年度热稳定性指数分别提升了70%与8.5%。