针对日光温室砌块承重墙体存在热稳定层,限制利用日间免费得到的太阳能用于夜间加热,致使室内空气昼夜温差大,不利于作物生长的问题,该文构建一种带重力循环环形管的新型主动蓄放热复合墙体,利用传热学理论建立该墙体非稳态传热模型,耦合室内空气热平衡方程,借助Matlab进行数值模拟。结果表明：在寒冷地区的冬季,新型主动蓄放热墙体夜间可使室内空气温度提高1.21 ℃,相比无重力循环环形管墙体提高13.12%;日有效积温提高7.88 ℃·h,相比提高4.84%;日平均热负荷可降低4769.24 W/d,相比降低17.35%。该墙体能增强主动蓄放热能力,将更多太阳能转移到夜间使用,可有效降低日间过高室温、提升夜间过低室温,减小室内气温日较差,有利于作物“四段变温管理”,促进冬季作物快速生长。
Abstract
To mitigate the issue of a thermally stable layer in block-bearing walls of solar greenhouses, which restricts the utilization of free solar energy at night, leading to a significant temperature disparity between daytime and nighttime indoor air, this paper introduces a novel active heat storage and discharge composite wall featuring a gravity circulation annular tube. The model is established based on heat transfer theory, incorporating the unsteady heat transfer of the wall, coupling it with the heat balance equation of indoor air, and executing numerical simulations utilizing Matlab. The results indicate that in cold regions during winter, the new active thermal storage wall elevates the indoor air temperature by 1.21 °C at night, marking a 13.12% increase compared to a wall lacking a gravity circulation annulus. Moreover, the daily effective temperature accumulation is 7.88 °C·h higher, representing a 4.84% improvement over a wall without a gravity circulation annulus. The average daily heat load experiences a reduction of 4769.24 W/d, accounting for a 17.35% decrease compared to a wall without a gravity circulation annulus. This innovative wall enhances the active heat storage and release capabilities, facilitating the transfer of more solar energy for nighttime use. It effectively curtails excessive daytime room temperatures, augments nighttime room temperatures, and minimizes the daily variation in indoor air temperature. Such improvements are conducive to the four-stage variable temperature management of crops, promoting the rapid growth of winter crops.
关键词
太阳能建筑 /
蓄热 /
数值模拟 /
日光温室 /
气温日较差 /
墙体
Key words
solar buildings /
heat storage /
numerical simulation /
solar greenhouse /
daily temperature range /
wall
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