The conventional heat flow meter (HFM) method is used to measure the thermal performance of building walls. Typically, this method is applicable for measurements on lightweight walls and when the difference between the indoor and outdoor temperatures exceeds 10 °C. However, modern buildings are constructed using highly insulated high-performance heavy-weight walls. Therefore, an in-situ measurement method is required to overcome the limited measurement environment of the conventional HFM method. In this study, a novel stored heat flux (SHF) method is proposed to overcome the limitations of the existing HFM method. This method estimates the stored heat flux in the wall using the thermal energy-conservation equation of the enclosed system and uses a decrement factor and time lag to calculate the thermal transmittance (U-value). The proposed method can be applied to heavy-weight walls in the cooling season when the difference between the indoor and outdoor temperatures is less than 10 °C. Furthermore, the design U-value can be estimated with higher accuracy than that observed in the conventional HFM method. The results of the relative error analysis for the U-values show that the conventional HFM method was approximately 68 % of the design U-value, while the proposed SHF method was approximately 15 %.

中文翻译：

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建筑墙体热透射率的原位测量：冷却季节重型墙体中存储的热通量的评估


传统的热流计 （HFM） 方法用于测量建筑物墙壁的热性能。通常，该方法适用于轻质墙壁上的测量以及室内和室外温差超过 10 °C 的情况。 然而，现代建筑是使用高度绝缘的高性能重型墙体建造的。因此，需要一种原位测量方法来克服传统 HFM 方法的有限测量环境。本研究提出了一种新的存储热通量 （SHF） 方法，以克服现有 HFM 方法的局限性。该方法使用封闭系统的热能守恒方程来估计壁中存储的热通量，并使用递减因子和时间滞后来计算热透射率（U 值）。该方法可应用于室内外温差小于 10 °C 的冷却季节的重型墙体。 此外，与传统 HFM 方法相比，可以更准确地估计设计 U 值。U 值的相对误差分析结果表明，传统的 HFM 方法约为设计 U 值的 68 %，而建议的 SHF 方法约为 15 %。