The appropriate use of internal thermal mass in buildings can reduce energy consumption while maintaining thermal comfort. A prerequisite for selecting suitable internal thermal mass is to establish its relationship with indoor air temperature and heat exchange. However, there is currently a lack of analytical models to describe this relationship. This study investigates the dynamic heat transfer performance of internal thermal mass under constant indoor air temperature, exponentially declining temperatures, and sinusoidal heating and cooling conditions. The results show that under constant indoor air temperature, materials with lower thermal conductivity (e.g., plywood with 0.17 W/m·°C) generate more thermal waves and experience faster surface temperature rises compared to materials with higher conductivity (e.g., reinforced concrete with 1.74 W/m·°C). In the case of exponentially declining indoor air temperature, heat exchange per unit area decreases with increasing thickness, with plywood (0.02 m) reaching its peak temperature at 6360 s, and reinforced concrete (0.2 m) at 9900 s. For sinusoidal temperature variations, the decrement factor for plywood and reinforced concrete decreases from 0.90 to 0.59 as thickness increases from 0.02 m to 0.06 m, while the time lag increases from 1.45 h to 3.16 h. The heat exchange is primarily related to the effective thermal capacity per unit area and the storage coefficient, which are determined by the physical properties of the internal thermal mass. These findings provide a quantitative basis for estimating the impact of internal thermal mass on indoor air temperature and heat exchange in the early stages of building design.

中文翻译：

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内部热质量的动态传热机制：不同温度条件下热导率和扩散率的影响


在建筑物中适当使用内部热质量可以在保持热舒适性的同时降低能耗。选择合适的内部热质量的前提条件是建立其与室内空气温度和热交换的关系。但是，目前缺乏描述这种关系的分析模型。本研究研究了在恒定室内空气温度、指数下降温度和正弦加热和冷却条件下内部热质量的动态传热性能。结果表明，在恒定的室内空气温度下，与导热率较高的材料（例如，1.74 W/m·°C 的钢筋混凝土）相比，导热系数较低的材料（例如，0.17 W/m·°C 的胶合板）会产生更多的热波，并且表面温度上升更快。在室内气温呈指数下降的情况下，单位面积的热交换随着厚度的增加而减小，胶合板（0.02 m）在 6360 s时达到峰值温度，钢筋混凝土（0.2 m）在 9900 s时达到峰值温度。对于正弦温度变化，当厚度从 0.02 m 增加到 0.06 m 时，胶合板和钢筋混凝土的衰减因子从 0.90 增加到 0.59，而时间滞后从 1.45 h 增加到 3.16 h。热交换主要与单位面积的有效热容量和存储系数有关，而存储系数是由内部热质量的物理性质决定的。这些发现为估计建筑设计早期内部热质量对室内空气温度和热交换的影响提供了定量基础。